Auto Electric & Electronic System Problems & Solutions

The diagnostic technician role is vital for any automobile workshop. Without Auto Electric & Electronic System Problems & Solutions knowledge, a workshop cannot provide quality work. For gathering these knowledge, we have provided 500 problems & solutions as follows.

No.	Auto Electrical Problem	Common Symptoms	Possible Causes	Solution / Repair
1	Battery Dead	Engine does not crank	Discharged/failed battery	Charge or replace battery; check charging system
2	Weak Battery	Slow cranking	Low electrolyte/poor battery condition	Test battery and replace if necessary
3	Battery Terminal Corrosion	Starting difficulty	Corrosion/loose terminals	Clean and tighten terminals
4	Alternator Not Charging	Battery warning lamp ON	Alternator, regulator, belt or wiring fault	Test alternator and repair/replace faulty component
5	Overcharging	Battery overheating/swelling	Voltage regulator fault	Test charging voltage and repair regulator/alternator
6	Blown Fuse	One or more electrical functions stop	Short circuit or excessive current	Find the cause and replace fuse with the correct rating
7	Faulty Relay	Load does not operate	Burnt contacts/coil failure	Test and replace relay
8	Broken Wiring	Intermittent or complete function failure	Open circuit/damaged wire	Check continuity and repair wiring
9	Short Circuit	Fuse repeatedly blows	Wire-to-ground or wire-to-wire short	Locate and repair the short circuit
10	Poor Ground Connection	Multiple electrical problems	Corroded/loose ground	Clean and secure ground connections
11	Starter Motor Fault	Engine does not crank	Worn brushes, solenoid or motor fault	Test and repair/replace starter
12	Starter Solenoid Fault	Clicking but no cranking	Solenoid contacts/coil failure	Test and replace/rebuild solenoid
13	Ignition Switch Fault	No ignition power	Worn switch/internal contacts	Test and replace ignition switch
14	Headlamp Failure	Headlamp not working	Bulb, fuse, relay or wiring fault	Test circuit and repair/replace faulty part
15	Turn Signal Failure	Indicators do not flash	Bulb, fuse, relay/flasher or BCM fault	Diagnose circuit and replace faulty component
16	Brake Light Failure	Brake lamps do not illuminate	Bulb, fuse or brake switch fault	Test switch/circuit and repair
17	Hazard Lamp Failure	Hazard lights unavailable	Switch, fuse, flasher or BCM fault	Diagnose and repair circuit
18	Horn Not Working	No horn sound	Horn, relay, fuse or switch fault	Test relay and horn circuit
19	Wiper Failure	Wipers do not operate	Motor, relay, switch or wiring fault	Test motor and control circuit
20	Power Window Failure	Window does not move	Motor, switch, fuse or wiring fault	Diagnose and repair/replace component
21	Central Locking Failure	Doors do not lock/unlock	Actuator, BCM, fuse or wiring fault	Diagnose locking circuit
22	Remote Keyless Entry Failure	Remote does not operate locks	Weak battery, lost synchronization or receiver fault	Replace key battery and perform diagnosis/reprogramming if required
23	Immobilizer Fault	Engine cranks but will not start	Key/transponder/immobilizer communication fault	Scan system and perform authorized key/immobilizer diagnosis
24	Fuel Pump Electrical Fault	Engine cranks but does not start	Fuse, relay, wiring or pump fault	Check power supply and fuel-pump circuit
25	Fuel Injector Electrical Fault	Misfire/poor starting	Open/short circuit or injector failure	Check injector resistance, wiring, and ECU command
26	Ignition Coil Fault	Misfire/no-start	Coil or power/ground fault	Test coil and ignition circuit
27	Electronic Throttle Fault	Poor acceleration/limp mode	Throttle motor/sensor/wiring fault	Scan ECU and test throttle system
28	Sensor Circuit Fault	Warning lamp/poor performance	Sensor failure or wiring problem	Check sensor signal, power and ground
29	CAN Bus Communication Fault	Multiple warning lamps/communication errors	Open/shorted CAN wiring or faulty module	Check CAN-H/CAN-L, termination and modules
30	ECU Power Supply Fault	Engine or system does not operate	Fuse, relay, power, or ground failure	Verify ECU power, ground, and communication
31	ABS Warning Light	ABS lamp remains ON	Wheel-speed sensor, wiring or ABS module fault	Scan ABS and inspect sensors/wiring
32	ESC Warning Light	Stability-control warning	Sensor, ABS/ESC module or calibration fault	Scan system and perform required calibration
33	Airbag Warning Light	SRS lamp remains ON	Sensor, wiring, connector or SRS module fault	Scan SRS and repair according to manufacturer procedure
34	Electric Power Steering Fault	Heavy steering/EPS warning	EPS motor, sensor, power or communication fault	Scan EPS and check power, ground and signals
35	TPMS Warning	Tire-pressure warning	Low pressure or sensor fault	Check tire pressure and diagnose TPMS
36	Parking Sensor Failure	No parking warning	Sensor, wiring or parking module fault	Scan and test individual sensors
37	ADAS Warning	Driver-assistance functions unavailable	Camera/radar obstruction, calibration or electrical fault	Inspect, scan and calibrate according to specification
38	Instrument Cluster Failure	Gauges/display not working	Power, communication or cluster fault	Check supply, ground, CAN communication and cluster
39	HVAC Blower Failure	No cabin airflow	Blower motor, resistor/module, fuse or wiring fault	Test blower circuit and replace faulty component
40	Infotainment Failure	Display/audio unavailable	Fuse, power, communication or software/module fault	Check power/network and diagnose infotainment module
41	Auto-Dimming Mirror Failure	Mirror does not dim	Sensor/power/mirror electronics fault	Check power and replace faulty mirror component
42	Seat Adjustment Failure	Power seat does not move	Motor, switch, fuse or wiring fault	Test motor and control circuit
43	Battery Drain	Battery goes flat after parking	Parasitic electrical load	Perform parasitic-current test and isolate the circuit
44	Charging Warning Lamp	Battery/charging lamp ON	Alternator or charging circuit fault	Check alternator output, belt, wiring and regulator
45	Engine Warning Lamp	Check-engine light ON	ECU-detected fault	Retrieve DTCs and diagnose the underlying cause
46	Poor Electrical Connection	Intermittent operation	Loose/corroded connector	Inspect, clean, and securely reconnect
47	Ground Loop/Noise	Audio or electronic noise	Poor grounding or electrical interference	Inspect grounding and wiring layout
48	Fuse Box Overheating	Burnt connector/fuse area	Loose connection or excessive current	Identify root cause and repair connector/circuit
49	Water Intrusion	Random electrical faults	Water entering connectors/modules	Locate leak, dry/repair connectors and protect module
50	OBD-II Communication Failure	Scan tool cannot communicate	DLC power/ground, CAN, or module fault	Check DLC pins, power, ground, and communication lines

No.	Auto Electrical Problem	Common Symptoms	Possible Causes	Solution / Repair
51	Starter Motor Spins Slowly	Slow engine cranking	High resistance, weak battery, worn starter	Test battery and voltage drop; repair starter/cables
52	Starter Motor Spins but Engine Does Not Crank	Starter runs without turning engine	Starter drive/Bendix failure	Inspect and replace starter drive
53	Starter Stays Engaged	Starter continues after engine starts	Solenoid or ignition-switch fault	Inspect solenoid and ignition circuit
54	Alternator Belt Slipping	Charging fluctuation, belt noise	Loose/worn belt	Adjust or replace belt
55	Alternator Bearing Noise	Whining/grinding noise	Worn bearing	Replace bearing or alternator
56	Alternator Diode Fault	Battery drain or electrical noise	Failed rectifier diode	Test diode/charging ripple and repair alternator
57	Voltage Regulator Failure	Undercharging/overcharging	Regulator fault	Test charging voltage and replace regulator/alternator
58	Battery Sensor Fault	Incorrect battery-management warnings	Sensor or wiring fault	Check sensor, connector and wiring
59	Battery Terminal Loose	Intermittent starting/electrical failure	Loose connection	Clean and tighten terminals
60	Battery Cable High Resistance	Slow cranking/voltage drop	Corrosion or damaged cable	Perform voltage-drop test and replace cable
61	Main Ground Cable Fault	Multiple intermittent faults	Broken/corroded ground strap	Repair or replace ground strap
62	Fuse Keeps Blowing	Same circuit repeatedly stops	Short circuit/overload	Find short or excessive load before replacing fuse
63	Incorrect Fuse Rating	Wiring overheating/failure	Wrong fuse installed	Install manufacturer-specified fuse
64	Relay Contacts Burnt	Electrical load works intermittently	Excessive current/relay wear	Replace relay and investigate excessive load
65	Relay Coil Open	Controlled component does not operate	Broken relay coil	Test coil resistance and replace relay
66	Connector Pin Corrosion	Intermittent electrical operation	Moisture/corrosion	Clean or replace terminals and seal connector
67	Connector Pin Loose	Intermittent signal	Poor terminal tension	Repair or replace terminal
68	Wire Open Circuit	Component completely inoperative	Broken conductor	Perform continuity test and repair wire
69	Wire Insulation Damaged	Short/intermittent faults	Chafing or heat damage	Repair insulation or replace wiring
70	Ground Short	Fuse blows, or circuit stops	Positive wire contacting ground	Locate and repair short
71	Power Supply Drop	ECU/component operates abnormally	High-resistance connection	Perform voltage-drop testing
72	CAN-H Open Circuit	Communication errors	Broken CAN-H wire	Test CAN network and repair wiring
73	CAN-L Open Circuit	Multiple module communication faults	Broken CAN-L wire	Repair CAN-L circuit
74	CAN Bus Short to Ground	Several ECUs unavailable	CAN wire shorted to ground	Isolate network and repair short
75	CAN Bus Short to Power	Communication failure	CAN wire contacting B+	Locate and repair short
76	CAN Bus Termination Fault	Network communication instability	Incorrect termination resistance	Check termination resistors and network wiring
77	LIN Bus Communication Fault	Single body function unavailable	LIN wire/master/slave fault	Check LIN communication and wiring
78	ECU Ground Fault	ECU resets or stops working	Poor ECU ground	Test and repair ECU ground
79	ECU Internal Fault	Persistent DTC/no communication	Internal electronic failure	Confirm power, ground, nd and network before ECU replacement
80	ECU Software/Calibration Fault	Incorrect system operation	Software/calibration issue	Perform approved software update/reprogramming
81	Crankshaft Sensor Fault	No-start/intermittent stalling	Sensor or wiring failure	Check signal and replace faulty sensor
82	Camshaft Sensor Fault	Hard starting/misfire	Sensor or circuit fault	Test sensor signal and wiring
83	Coolant Temperature Sensor Fault	Poor fuel economy/incorrect fan operation	Sensor resistance/signal fault	Test sensor and replace if defective
84	MAF Sensor Fault	Poor acceleration/rough running	Contamination or electrical fault	Inspect, clean if permitted, and test/replace
85	MAP Sensor Fault	Poor engine performance	Sensor/vacuum/wiring problem	Check reference voltage, signal and vacuum
86	Throttle Position Sensor Fault	Poor throttle response/limp mode	Sensor or wiring fault	Check signal and replace throttle assembly/sensor if required
87	Oxygen Sensor Fault	Poor fuel economy/emissions	Sensor aging, wiring or heater fault	Check sensor data and heater circuit
88	Accelerator Pedal Sensor Fault	No/limited acceleration	Pedal sensor or wiring fault	Check dual sensor signals and wiring
89	Fuel Pump Relay Fault	Engine cranks but does not start	Relay/control fault	Check relay command and fuel-pump power
90	Fuel Pump Wiring Fault	Low/no fuel pressure	Open/short/high resistance	Perform voltage-drop and current tests
91	Injector Wiring Fault	Misfire/no injection	Open/short circuit	Check injector power and ECU control signal
92	Ignition Coil Power Fault	Multiple misfires/no-start	Fuse, relay or wiring problem	Verify coil power and ground/control
93	Glow Plug System Fault	Difficult diesel starting	Glow plug, relay/module or wiring fault	Test glow plugs and control module
94	Glow Plug Control Module Fault	Glow-plug warning/problem starting	Module or communication fault	Scan module and test power/control circuits
95	Cooling Fan Not Working	Engine overheating	Fan motor, relay, fuse,e or ECU control fault	Test fan motor and control circuit
96	Cooling Fan Runs Continuously	Fan remains ON	Sensor/relay/ECU fault	Check coolant-temperature data and relay/control circuit
97	Electric Water Pump Fault	Overheating/warning	Pump motor, module,le or wiring fault	Diagnose pump power, control, or communication
98	EGR Electrical Fault	Poor performance/emissions warning	EGR actuator or position sensor fault	Scan ECU and test EGR circuit
99	Variable Valve Timing Actuator Fault	Poor performance/check-engine light	Solenoid, wiring, or oil-control problem	Test actuator circuit and related system
100	Idle Stop/Start System Fault	Auto stop/start unavailable	Battery, sensor, ECU, or system-condition fault	Check battery condition, DTCs, and system inputs

No.	Auto Electrical Problem	Common Symptoms	Possible Causes	Solution / Repair
101	Transmission Solenoid Fault	Harsh or incorrect shifting	Solenoid, wiring, or connector fault	Test solenoid resistance and control circuit
102	Transmission Speed Sensor Fault	Erratic shifting/speed indication	Sensor or wiring failure	Test sensor signal and replace if defective
103	Transmission Range Sensor Fault	Gear position incorrect/no start	Sensor misalignment or wiring fault	Inspect, adjust, or replace sensor
104	Shift Lock Solenoid Fault	Gear selector remains locked	Solenoid, brake switch or wiring fault	Check brake signal and solenoid circuit
105	ABS Wheel-Speed Sensor Fault	ABS/ESC warning lights	Damaged sensor, wiring or tone ring	Inspect sensor and wiring; replace faulty component
106	ABS Sensor Wiring Damage	Intermittent ABS operation	Broken/chafed wiring	Repair or replace wiring
107	ABS Hydraulic Pump Fault	ABS warning/poor ABS operation	Pump motor or control-module fault	Test pump circuit and ABS module
108	ABS Solenoid Valve Fault	ABS malfunction	Valve or electrical circuit fault	Scan ABS and test valve circuit
109	Brake Pressure Sensor Fault	ABS/ESC warning	Sensor or wiring problem	Check pressure signal and wiring
110	Steering Angle Sensor Fault	ESC warning/incorrect steering assistance	Sensor calibration or communication fault	Diagnose and perform required calibration
111	Yaw Rate Sensor Fault	ESC/traction warning	Sensor or wiring failure	Check sensor data and calibration
112	Electric Power Steering Motor Fault	Heavy steering/EPS warning	Motor, power supply or control fault	Test EPS power, ground and motor
113	EPS Control Module Fault	Steering assistance unavailable	Module or communication failure	Check power, ground and CAN communication
114	Active Suspension Actuator Fault	Uneven ride/handling warning	Actuator or wiring fault	Test actuator and suspension control system
115	Airbag Sensor Fault	SRS warning lamp	Crash sensor/wiring fault	Scan SRS and inspect connectors
116	Airbag Squib Circuit Fault	Airbag warning lamp	Open/short circuit in deployment circuit	Diagnose according to manufacturer SRS procedure
117	Seatbelt Pretensioner Fault	SRS warning	Pretensioner or wiring fault	Scan SRS and repair using approved procedure
118	Occupant Detection Sensor Fault	Passenger-airbag warning	Seat sensor or wiring fault	Test sensor and wiring
119	Rain Sensor Fault	Automatic wipers do not work correctly	Sensor, windshield mounting,nting or wiring issue	Inspect sensor and calibration
120	Light Sensor Fault	Automatic lights malfunction	Sensor or wiring failure	Test sensor signal and circuit
121	Headlamp Leveling Fault	Headlamp beam too high/low	Level sensor/actuator fault	Check leveling sensors and actuators
122	Adaptive Headlamp Fault	Adaptive lighting unavailable	Motor, sensor or control-module fault	Scan system and test actuator
123	Daytime Running Light Failure	DRLs not operating	LED module, fuse or BCM fault	Check power, ground and BCM control
124	Interior Light Failure	Cabin lights do not operate. te	Bulb/LED, fuse, switch or BCM fault	Diagnose lighting circuit
125	Auto-Dimming Mirror Fault	Mirror does not dim	Sensor, power or mirror electronics fault	Check power and replace faulty component
126	Power Window Motor Fault	Window moves slowly or not at all	Motor wear or electrical fault	Test motor current and replace if necessary
127	Power Window Switch Fault	Window works from one switch only	Switch contact failure	Test and replace switch
128	Window Anti-Pinch Fault	Window reverses unexpectedly	Calibration or sensor/control issue	Inspect system and perform initialization
129	Door Lock Actuator Fault	One door won’t lock/unlock	Actuator or wiring failure	Test actuator and wiring
130	BCM Fault	Multiple body functions fail	Module power, ground, or internal fault	Check BCM power/network before replacement
131	Hood/Door Switch Fault	Alarm or interior-light problems	Faulty switch/sensor	Test switch status and wiring
132	Horn Relay Fault	Horn does not operate	Relay contacts/coil failure	Test and replace relay
133	Electric Horn Fault	Weak/no horn sound	Horn diaphragm/coil failure	Check voltage and replace horn
134	Wiper Motor Fault	Wipers stop or move slowly	Motor wear or electrical fault	Test motor and replace if required
135	Wiper Park Switch Fault	Wipers stop in wrong position	Internal park-switch failure	Test and replace wiper motor/park circuit
136	Washer Pump Fault	Washer fluid does not spray	Pump, fuse, or wiring fault	Test pump voltage and replace if necessary
137	HVAC Blower Motor Fault	No or weak cabin airflow	Blower motor, resistor/module, or wiring fault	Test blower circuit and replace faulty part
138	Blower Resistor/Control Module Fault	Some blower speeds unavailable	Resistor/module failure	Test and replace resistor/control module
139	A/C Compressor Clutch Fault	A/C not cooling	Clutch, relay, fuse or control fault	Check electrical command and clutch circuit
140	A/C Pressure Sensor Fault	A/C cuts out or doesn’t operate	Pressure sensor or wiring failure	Check refrigerant pressure and sensor signal
141	Electric A/C Compressor Fault	Hybrid/EV A/C not cooling	Compressor, inverter/control or HV-system fault	Diagnose using manufacturer procedure
142	HVAC Temperature Sensor Fault	Incorrect cabin temperature	Sensor or wiring fault	Check sensor resistance/signal
143	Seat Heating Fault	Heated seat does not warm	Heater element, switch or module fault	Test heater resistance and control circuit
144	Seat Position Memory Fault	Saved seat position unavailable	Memory module, switch or motor fault	Check module, power and communication
145	Sunroof Electrical Fault	Sunroof doesn’t open/close	Motor, switch, fuse or calibration fault	Test circuit and initialize system
146	Parking Assist Sensor Fault	False/no parking warnings	Dirty/damaged sensor or wiring fault	Clean, test and replace sensor if necessary
147	Parking Camera Failure	No rear/360° camera image	Camera, power, wiring or display fault	Check power, video/network connection
148	Automatic Parking Fault	Auto-parking unavailable	Sensor, camera, steering or ECU fault	Scan system and verify sensor inputs
149	TPMS Sensor Battery Low	TPMS warning/one sensor missing	Internal sensor battery depleted	Replace TPMS sensor and register it
150	TPMS Communication Fault	Tire-pressure data missing	Sensor, receiver, or communication fault	Scan TPMS, identify missing sensor and repair/register

No.	Auto Electric Problem	Common Symptoms	Possible Causes	Solution / Repair
151	Head-Up Display Failure	HUD does not appear	Power, display unit, fuse, or communication fault	Check power, ground, and communication; diagnose HUD module
152	Instrument Cluster Backlight Failure	Gauges visible but illumination is dim/off	LED, power, or cluster fault	Test power supply and cluster circuit
153	Instrument Cluster Communication Fault	Multiple gauges/warnings unavailable	CAN/network or module fault	Check CAN communication and module power
154	Speedometer Failure	Speed remains zero	Wheel-speed sensor CAN or cluster fault	Check vehicle-speed signal and network
155	Tachometer Failure	RPM gauge not working	Engine-speed signal or cluster fault	Check crankshaft signal and CAN data
156	Fuel Gauge Incorrect Reading	Fuel level inaccurate	Fuel-level sensor, wiring,g or cluster fault	Test sender resistance/signal and wiring
157	Coolant Temperature Gauge Fault	Temperature reading incorrect	Temperature sensor or communication fault	Test sensor and ECU data
158	Warning Lamp Stays ON	Warning indicator remains illuminated	Stored DTC or sensor fault	Scan relevant ECU and diagnose root cause
159	Check Engine Lamp Not Illuminating	MIL fails bulb/self-test	LED, cluster or ECU communication fault	Check cluster and ECU communication
160	Illuminated Switch Failure	Switch works, but light is off	LED/bulb or circuit fault	Test switch illumination circuit
161	Navigation System Failure	Incorrect/no navigation	GPS antenna, module or software fault	Check antenna, signal and navigation module
162	GPS Antenna Fault	Vehicle location inaccurate	Damaged antenna/coaxial cable	Test antenna and cable
163	Infotainment Touchscreen Failure	Touchscreen unresponsive	Display, software, re or communication fault	Check power, reset system and diagnose module
164	Audio Amplifier Failure	No or distorted sound	Amplifier power, ground or communication fault	Check amplifier supply and audio/network connections
165	Speaker Failure	One speaker has no sound	Speaker coil, wiring, ing or connector fault	Test speaker resistance and wiring
166	Bluetooth Connection Failure	Phone will not connect	Software/module/pairing issue	Reset connection and diagnose communication module
167	USB Port Failure	Device does not charge/conect,	Fuse, port,t or wiring fault	Check port power and communication lines
168	Wireless Charging Failure	Phone does not charge	Charging pad, power supply or module fault	Check supply and charging module
169	Voice Control Failure	Voice commands not recognized	Microphone, software or communication fault	Test microphone and communication system
170	Rear Entertainment System Failure	Rear display unavailable	Power, display or control-module fault	Check supply, wiring and display module
171	DSRC/V2X Communication Fault	Vehicle-infrastructure communication unavailable	Antenna, module or network fault	Check antenna, module and communication network
172	Telematics Control Unit Fault	Connected services unavailable	TCU power, antenna, network or software fault	Scan TCU and check communication system
173	Emergency Call System Fault	eCall warning displayed	TCU, antenna or backup battery fault	Diagnose telematics/eCall system
174	Remote Start Failure	Vehicle won’t start remotely	Key authorization, battery, BCM or security condition	Check remote-start conditions and system DTCs
175	Smart Key Not Detected	“Key not detected” warning	Key battery, antenna, or receiver fault	Replace key battery and test key antennas
176	Push-Button Start Failure	Start button does not start engine	Switch, brake/clutch signal, key or BCM fault	Check authorization and start-control inputs
177	Immobilizer Antenna Fault	Key not recognized	Antenna coil, wiring or module fault	Test antenna and immobilizer circuit
178	Alarm System False Triggering	Alarm activates without intrusion	Door switch, hood switch or sensor fault	Monitor switch inputs and repair faulty sensor
179	Security Indicator Fault	Security lamp operates incorrectly	Immobilizer/BCM or cluster communication issue	Scan security system and check communication
180	Power Door Lock Intermittent	Locks work occasionally	Weak actuator, connector, or BCM fault	Check actuator current and wiring
181	Door Module Communication Fault	Door functions unavailable	CAN/LIN or door-module power fault	Check power, ground, round, and network
182	Mirror Adjustment Failure	Electric mirror won’t move	Motor, switch or wiring fault	Test mirror motor and switch
183	Power Folding Mirror Fault	Mirror won’t fold/unfold	Motor, gear, module or wiring fault	Test folding motor and control circuit
184	Mirror Heating Failure	Mirror does not defrost	Heater element, fuse or wiring fault	Check heater resistance and power supply
185	Rear Defogger Failure	Rear glass does not clear	Grid, relay, fuse or switch fault	Test grid continuity and power supply
186	Heated Windshield Failure	Windshield heating unavailable	Heater circuit, relay or control fault	Check circuit and heating elements
187	Cigarette/Accessory Socket Failure	Accessory socket has no power	Fuse or socket wiring fault	Check fuse and socket voltage
188	USB Power Supply Fault	USB devices won’t charge	Fuse, converter or port fault	Test power supply and USB module
189	12V Accessory Battery Drain	Battery becomes weak after parking	Connected accessory drawing current	Perform parasitic-current test and isolate load
190	Parasitic Current Excessive	Battery repeatedly discharges	Module remains awake/accessory load	Measure sleep current and identify offending circuit
191	Power Distribution Module Fault	Several electrical systems fail	Internal module, fuses,e or communication fault	Verify supply/ground and diagnose module
192	Junction Box Fault	Multiple circuits unavailable	Internal connection/fuse/relay fault	Inspect junction box and terminal connections
193	Main Power Cable Fault	Vehicle loses electrical power	Damaged/high-resistance cable	Perform voltage-drop test and replace cable
194	Ground Strap Broken	Starting and electronic problems	Engine/body ground strap damaged	Replace ground strap and verify voltage drop
195	Body Ground Corrosion	Intermittent electrical faults	Corroded chassis ground point	Clean, repair,ir and protect ground connection
196	Water-Damaged ECU Connector	Multiple intermittent faults	Moisture/corrosion in connector	Locate water entry, repair connector and seal area
197	Wire Harness Chafing	Intermittent shorts/DTCs	Harness rubbing against body/engine	Repair wiring and secure harness properly
198	Heat-Damaged Wiring	Melted insulation/short circuits	Excessive heat or poor routing	Replace damaged wiring and correct routing
199	Electrical Noise Interference	Radio/static or electronic disturbances	Poor grounding or electromagnetic interference	Check grounds, shielding, and wiring routing
200	Incorrect Electrical Accessory Installation	Random electrical faults/battery drain	Poor aftermarket wiring	Rewire using correct fuse, relay, grounding, and manufacturer-approved methods

No.	Auto Electric Problem	Common Symptoms	Possible Causes	Solution / Repair
201	Alternator Stator Fault	Low charging output	Open/shorted stator winding	Test winding resistance and output; repair/replace alternator
202	Alternator Rotor Fault	No/low charging	Open rotor winding or slip-ring problem	Test rotor continuity and replace/repair faulty component
203	Alternator Rectifier Fault	Battery drain/AC ripple	Failed diode or rectifier	Test diodes and replace rectifier
204	Alternator Slip Ring Wear	Unstable charging	Worn/dirty slip rings	Inspect, clean,ean or replace slip rings
205	Alternator Brush Wear	Intermittent charging	Worn brushes	Replace brush assembly/regulator
206	Charging Cable Open Circuit	Battery not charging	Broken charging wire/fusible link	Perform continuity/voltage-drop test and repair
207	Charging Cable High Resistance	Low charging voltage	Corrosion or loose connection	Clean connections or replace cable
208	Battery Temperature Sensor Fault	Incorrect charging behavior	Sensor/wiring failure	Test sensor and replace if defective
209	Battery Current Sensor Fault	Battery-management warning	Sensor or connector problem	Check sensor signal and wiring
210	Battery State-of-Charge Miscalculation	Charging/start-stop problems	Battery sensor calibration issue	Diagnose BMS and perform required reset/calibration
211	Battery Registration Required	New battery causes warnings	Battery replacement not registered	Register/program battery according to vehicle procedure
212	Start/Stop System Unavailable	Engine doesn’t stop automatically	Low battery charge or system fault	Test battery and check start/stop DTCs
213	Starter Control Relay Fault	No starter operation	Relay failure	Test relay input/output and replace
214	Starter Control Signal Missing	Starter doesn’t engage	ECU, immobilizer, or wiring issue	Verify start authorization and control signal
215	Starter Voltage Drop Excessive	Slow cranking	High resistance in cables/connections	Perform positive/ground-side voltage-drop tests
216	Ignition Coil Driver Fault	Misfire/no spark	ECU driver or wiring fault	Check control signal and ECU circuit
217	Spark Plug Wiring Fault	Misfire	Damaged ignition wiring	Inspect and replace damaged wiring
218	Glow Plug Open Circuit	Difficult cold starting	Burnt-out glow plug	Measure resistance/current and replace faulty plug
219	Glow Plug Relay Stuck ON	Glow plugs overheat	Relay contacts stuck	Test relay and replace
220	Fuel Injector Short Circuit	Misfire/no-start	Injector coil short	Measure resistance/current and replace injector
221	Fuel Injector Open Circuit	Cylinder not firing	Broken injector coil/wiring	Check continuity and repair/replace
222	Injector Driver Circuit Fault	Multiple injector faults	ECU driver/wiring problem	Verify power, ground, and ECU control signals
223	Fuel Pressure Sensor Fault	Poor starting/performance	Sensor or wiring problem	Check reference voltage and signal
224	Fuel Pump Control Module Fault	Low/no fuel pressure	Module, power or communication fault	Check module supply, ground and command
225	Electronic Fuel Pressure Regulator Fault	Incorrect fuel pressure	Regulator or wiring failure	Test regulator and control circuit
226	Turbocharger Electronic Actuator Fault	Low power/boost warning	Actuator motor, sensor or wiring fault	Scan ECU and test actuator
227	Electronic Wastegate Fault	Boost instability	Actuator/linkage/control fault	Test actuator position and wiring
228	EGR Position Sensor Fault	EGR DTC/poor performance	Sensor or wiring fault	Check feedback signal and replace component if required
229	Electronic EGR Valve Stuck	Poor running/emissions	Motor or valve mechanism fault	Diagnose actuator and repair/replace valve
230	Electronic VVT Solenoid Fault	Poor performance/timing DTC	Solenoid, oil contamination, or wiring fault	Test solenoid and control circuit
231	Camshaft Actuator Position Fault	Timing-related DTC	Actuator/sensor/ECU control issue	Check actuator command and feedback
232	Electronic Thermostat Fault	Incorrect engine temperature	Thermostat heater/control fault	Test heater circuit and thermostat
233	Cooling Fan Control Module Fault	Fan unavailable/continuous operation	Module or communication fault	Check power, ground and control signal
234	Radiator Fan Resistor Fault	Some fan speeds unavailable	Resistor failure	Test and replace resistor if fitted
235	Engine Oil Pressure Sensor Fault	Oil warning/inaccurate reading	Sensor or wiring fault	Test sensor and circuit; verify actual oil pressure
236	Oil Level Sensor Fault	Incorrect oil-level warning	Sensor or wiring problem	Inspect sensor and connector; test signal
237	Knock Sensor Circuit Fault	Engine warning/reduced performance	Sensor or wiring failure	Test sensor circuit and replace if necessary
238	Fuel Tank Pressure Sensor Fault	EVAP warning	Sensor or wiring fault	Test pressure sensor and circuit
239	EVAP Purge Valve Electrical Fault	Check engine light/rough idle	Solenoid or wiring failure	Test valve resistance and control
240	EVAP Vent Valve Fault	EVAP DTC/refueling issue	Valve, wiring, or blockage	Test valve and inspect EVAP circuit
241	Diesel Intake Air Heater Fault	Poor cold starting	Heater, relay or wiring fault	Test heater circuit and control module
242	Diesel Exhaust Temperature Sensor Fault	DPF/engine warning	Sensor or wiring failure	Check temperature readings and circuit
243	DPF Differential Pressure Sensor Fault	DPF warning	Sensor tubes/sensor/wiring problem	Inspect tubes and test sensor
244	DPF Regeneration Control Fault	DPF regeneration unavailable	Sensor, ECU or actuator fault	Scan system and correct root cause
245	SCR/AdBlue Pump Fault	Emission warning	Pump, wiring,ng or control-module fault	Diagnose SCR system and repair pump circuit
246	NOx Sensor Fault	Emission warning/limp mode	Sensor, heater or wiring failure	Scan system and test sensor circuit
247	Oxygen Sensor Heater Fault	Check engine light	Heater element/fuse/wiring fault	Test heater resistance and power supply
248	A/F Sensor Circuit Fault	Poor fuel control	Sensor or heater/control fault	Check sensor power, ground, and signal
249	Engine ECU Communication Interruption	Engine warning/no-start	CAN, power, ground, or ECU fault	Verify ECU power/ground and network communication
250	Powertrain CAN Network Fault	Multiple powertrain DTCs	CAN wiring, connector, or module fault	Check CAN resistance, wiring, and affected modules

No.	Auto Electric Problem	Common Symptoms	Possible Causes	Solution / Repair
251	DPF Pressure Sensor Hose Blockage	Incorrect DPF readings	Soot/condensation blocking hose	Inspect and clean/replace hoses
252	DPF Temperature Sensor Fault	Regeneration problems	Sensor or wiring failure	Test sensor signal and replace if required
253	AdBlue/DEF Level Sensor Fault	Incorrect DEF level warning	Sensor or wiring fault	Test level sensor and circuit
254	AdBlue/DEF Quality Sensor Fault	Emission warning	Sensor contamination or failure	Diagnose sensor and replace if necessary
255	SCR Injector Electrical Fault	SCR/AdBlue warning	Injector coil or wiring fault	Test injector resistance and control circuit
256	Exhaust Gas Temperature Sensor Fault	Regeneration/emission DTC	Sensor failure or open circuit	Check sensor resistance and wiring
257	Exhaust Pressure Sensor Fault	Engine/DPF warning	Sensor or pressure line problem	Inspect pressure lines and sensor
258	Throttle Actuator Position Fault	Limp mode/poor response	Position sensor or actuator fault	Check feedback signal and actuator
259	Electronic Throttle Motor Fault	No/limited acceleration	Motor failure or wiring problem	Test motor circuit and replace assembly if required
260	Accelerator Pedal Wiring Fault	Accelerator unresponsive	Open/short/high resistance	Perform wiring and voltage tests
261	Crankshaft Sensor Signal Intermittent	Stalling/intermittent no-start	Sensor gap, wiring, or connector issue	Inspect sensor and wiring
262	Camshaft Sensor Synchronization Fault	Hard starting/misfire	Timing or sensor signal problem	Check timing correlation and sensor signals
263	Engine Knock Sensor Wiring Fault	Knock-related DTC	Damaged wiring/connector	Repair wiring and verify signal
264	Engine Coolant Sensor Open Circuit	Cold/hot reading incorrect	Broken wire/sensor	Test circuit resistance and repair
265	Engine Coolant Sensor Short Circuit	Incorrect temperature reading	Short circuit in sensor/wiring	Test reference and signal circuits
266	MAF Sensor Power Supply Fault	Poor engine performance	Fuse, wiring or ECU supply fault	Check sensor power, ground and wiring
267	MAP Sensor Reference Voltage Fault	Poor acceleration/boost control	5V reference or wiring issue	Test reference voltage and repair circuit
268	Oxygen Sensor Signal Stuck	Fuel-trim DTC/poor economy	Sensor contamination or circuit fault	Check sensor operation and wiring
269	Fuel Trim Control Fault	Poor fuel economy/rough idle	Vacuum leak, sensor or injector issue	Diagnose live fuel-trim data and root cause
270	EVAP Leak Detection Pump Fault	EVAP warning	Pump or wiring fault	Test pump and control circuit
271	Fuel Tank Vent Valve Fault	Refueling difficulty/EVAP DTC	Valve stuck or electrical failure	Test valve and replace if necessary
272	Fuel Cap Detection Fault	EVAP warning	Cap, sensor, or wiring issue	Inspect cap and EVAP detection system
273	Engine Oil Level Sensor Wiring Fault	Oil-level warning	Open/short circuit	Check wiring and connector
274	Oil Pressure Switch Fault	Oil warning r..remains	Switch or wiring failure	Verify actual oil pressure and test switch
275	Electronic Oil Pump Fault	Low oil pressure/engine warning	Pump motor/module/wiring fault	Diagnose pump control and oil pressure
276	Electric Coolant Pump Wiring Fault	Overheating	Open/short/high resistance	Test power, ground, and control wiring
277	Turbo Boost Pressure Sensor Fault	Low/high boost	Sensor or wiring problem	Check sensor signal and boost system
278	Turbocharger Position Sensor Fault	Limp mode	Position feedback failure	Test sensor and actuator
279	Turbocharger Actuator Calibration Fault	Boost control problem	Lost calibration or mechanical issue	Perform approved actuator calibration
280	Variable Valve Timing Sensor Fault	Timing DTC/poor performance	Sensor, wiring, or timing issue	Test sensor and verify timing
281	VVT Solenoid Short Circuit	Engine warning/poor performance	Solenoid coil short	Measure resistance and repair circuit
282	VVT Solenoid Open Circuit	Timing control unavailable	Broken coil/wiring	Test continuity and replace faulty part
283	Electronic Wastegate Wiring Fault	Boost instability	Damaged wiring/connector	Inspect and repair wiring
284	Intake Runner Control Fault	Poor low/high-speed performance	Actuator, sensor or linkage fault	Test actuator and feedback signal
285	Swirl Flap Actuator Fault	Poor diesel performance	Motor, sensor or wiring fault	Diagnose actuator and repair/replace
286	EGR Control Solenoid Fault	EGR DTC/rough running	Solenoid or wiring fault	Test solenoid and control circuit
287	EGR Position Feedback Fault	EGR warning/limp mode	Position sensor or actuator fault	Check feedback signal and actuator
288	Fuel Rail Pressure Sensor Fault	Hard starting/poor running	Sensor or wiring fault	Test reference, signal and ground
289	Fuel Rail Pressure Control Valve Fault	Incorrect rail pressure	Valve, wiring or fuel-system problem	Test valve and verify rail pressure
290	High-Pressure Fuel Pump Control Fault	No-start/low power	Pump actuator, wiring, or ECU control	Check pump control and fuel pressure
291	Common-Rail Pressure Sensor Wiring Fault	Rail-pressure DTC	Open/short/high resistance	Test wiring and connector
292	Diesel Injector Correction Fault	Rough idle/misfire	Injector or electrical circuit problem	Check injector data and perform injector testing
293	Injector Coding/Programming Error	Rough running after injector replacement	Incorrect injector code	Enter correct injector calibration code
294	Glow Plug Control Communication Fault	Glow system unavailable	LIN/CAN or module fault	Check power, ground and communication
295	Engine Mount Active Control Fault	Excessive vibration	Electronic mount actuator/sensor fault	Diagnose mount control system
296	Engine Cooling Fan Communication Fault	Fan operates incorrectly	LIN/PWM/CAN or module fault	Check communication and control signal
297	Electric Radiator Shutter Fault	Reduced efficiency/engine warning	Actuator, position sensor, or wiring fault	Test shutter actuator and calibration
298	Active Grille Shutter Fault	Warning/incorrect airflow	Motor, position sensor, or obstruction	Inspect mechanism and electrical circuit
299	Engine Compartment Harness Ground Fault	Multiple intermittent engine DTCs	Poor ground connection	Clean/repair ground point and verify voltage drop
300	Powertrain Sensor Reference Voltage Short	Multiple sensor DTCs simultaneously	Shared 5V reference shorted	Isolate affected sensor/circuit and repair short

No.	Auto Electric Problem	Common Symptoms	Possible Causes	Solution / Repair
301	Transmission ECU Power Supply Fault	Transmission warning/no shifting	Fuse, relay, wiring, or ground fault	Check TCM power, ground, and fuses
302	Transmission ECU Communication Fault	Multiple transmission DTCs	CAN wiring or TCM fault	Check CAN network and TCM communication
303	Transmission Solenoid Open Circuit	Gear shifting problem	Broken solenoid coil/wiring	Test resistance and continuity; repair/replace
304	Transmission Solenoid Short Circuit	Harsh/incorrect shifting	Shorted coil or wiring	Test circuit and replace faulty component
305	Transmission Oil Temperature Sensor Fault	Incorrect shifting	Sensor or wiring fault	Test sensor resistance/signal
306	Clutch Position Sensor Fault	DCT/manual automated transmission problems	Sensor or wiring fault	Check sensor signal and calibration
307	Clutch Actuator Electrical Fault	DCT gear selection failure	Actuator motor/module/wiring fault	Test actuator and control circuit
308	CVT Step Motor Fault	Abnormal CVT operation	Motor or control circuit fault	Diagnose motor and TCM
309	CVT Ratio Sensor Fault	Incorrect ratio/limp mode	Sensor or wiring fault	Test sensor and wiring
310	Gear Selector Sensor Fault	Incorrect gear indication	Position sensor or wiring problem	Test selector signal and repair
311	Brake Pedal Switch Fault	Brake lights/shift-lock/stop-start malfunction	Switch misadjustment or failure	Test switch and replace/adjust
312	Clutch Pedal Switch Fault	Starting or cruise-control problem	Switch/wiring fault	Check switch operation and signal
313	Electronic Parking Brake Fault	EPB warning/parking brake unavailable	Motor, switch, module or wiring fault	Scan EPB and test actuator circuits
314	EPB Motor Fault	Parking brake won’t apply/release	Motor or wiring failure	Test motor and replace if required
315	EPB Switch Fault	EPB switch doesn’t respond	Switch or wiring fault	Test switch circuit
316	Brake Pad Wear Sensor Fault	Brake warning message	Sensor or wiring damage	Inspect and replace sensor where applicable
317	Brake Light Control Module Fault	Brake lights malfunction	Module, wiring, or communication fault	Check module inputs/outputs
318	Steering Wheel Angle Calibration Lost	ESC/EPS warning	Battery disconnect, alignment,or calibration issue	Perform manufacturer-specified calibration
319	Steering Torque Sensor Fault	Heavy/incorrect steering assist	Torque sensor or EPS module fault	Diagnose sensor and EPS system
320	Steering Column Lock Fault	Vehicle may not start/unlock steering	Electronic lock motor/module fault	Diagnose steering-lock system
321	Radar Sensor Power Fault	Adaptive cruise unavailable	Fuse, wiring, or power supply problem	Check radar power and ground
322	Radar Sensor Misalignment	ACC/ADAS unavailable	Impact or incorrect mounting	Inspect mounting and perform calibration
323	Front Camera Power Fault	Lane/ADAS functions unavailable	Fuse, wiring, or module fault	Check camera power, ground, and communication
324	Front Camera Calibration Fault	Lane functions disabled	Windshield replacement/alignment issue	Perform required camera calibration
325	Ultrasonic Sensor Fault	Parking assistance unavailable	Sensor damage or wiring fault	Test individual sensors and circuit
326	Blind-Spot Radar Fault	Blind-spot warning unavailable	Radar, wiring or module fault	Scan system and test radar
327	Rear Cross-Traffic Alert Fault	No rear cross-traffic warning	Radar/module/communication fault	Diagnose rear radar system
328	Lane Departure Camera Fault	Lane warning unavailable	Camera, wiring or software fault	Check camera system and calibration
329	ADAS ECU Communication Fault	Multiple ADAS warnings	CAN/Ethernet or ECU fault	Check network, power and ground
330	Forward Collision Warning Fault	Collision warning unavailable	Radar/camera/ADAS fault	Diagnose sensors and ADAS ECU
331	Automatic Emergency Braking Fault	AEB unavailable	Sensor, brake-control or communication fault	Scan ADAS/ABS systems and repair
332	Traffic Sign Recognition Fault	Signs not displayed	Camera/software/communication fault	Check camera and system software
333	Driver Monitoring Camera Fault	Driver monitoring unavailable	Camera, power or software fault	Test camera and control module
334	Night Vision Camera Fault	Night-vision display unavailable	Camera/module/power fault	Diagnose camera circuit and module
335	Headlamp Control Module Fault	Multiple lighting functions fail	Module power/network/internal fault	Check module supply and communication
336	LED Headlamp Driver Fault	LED lamp flickers/stays OFF	Driver module or wiring fault	Test driver and power supply
337	Headlamp Communication Fault	Lighting warning	CAN/LIN communication problem	Check network and headlamp module
338	Turn Signal LED Fault	Indicator warning/failure	LED module or wiring fault	Diagnose lamp assembly and wiring
339	Brake Lamp LED Fault	Brake lamp unavailable	LED module or control fault	Test lamp and control circuit
340	Rear Combination Lamp Fault	Several rear lights unavailable	Connector, wiring or lamp module fault	Inspect connector and lamp circuit
341	Fog Lamp Control Fault	Fog lamps don’t operate	Switch, relay, fuse or BCM fault	Check control circuit
342	Automatic High Beam Fault	High beam does not switch automatically	Camera/light sensor/control fault	Diagnose camera and lighting module
343	Ambient Light Sensor Fault	Automatic lighting behaves incorrectly	Sensor or wiring fault	Test sensor and circuit
344	Rain-Light Sensor Communication Fault	Auto wiper/light functions unavailable	LIN/CAN or sensor fault	Check communication and sensor
345	Wiper Control Module Fault	Wipers operate incorrectly	Module, power, or communication fault	Scan module and verify inputs/outputs
346	Wiper Speed Control Fault	Only one speed works	Switch, module, or motor control fault	Test speed-control circuit
347	Washer Fluid Level Sensor Fault	Low-fluid warning remains ON	Sensor or wiring fault	Test sensor and repair/replace
348	Rain-Sensing Wiper Calibration Fault	Automatic wipers inaccurate	Sensor calibration/mounting issue	Inspect windshield sensor and calibrate
349	Rear Wiper Motor Fault	Rear wiper does not operate	Motor, fuse or wiring fault	Test motor and control circuit
350	Rear Wiper Washer Control Fault	Rear washer/wiper unavailable	Switch, pump, relay or BCM fault	Diagnose control circuit and repair

No.	Auto Electric Problem	Common Symptoms	Possible Causes	Solution / Repair
351	Central Gateway Module Fault	Several ECUs cannot communicate	Gateway power, software, or internal fault	Check power, ground, network, and gateway DTCs
352	CAN Gateway Communication Fault	Multiple communication DTCs	CAN wiring or gateway failure	Test CAN lines and gateway communication
353	CAN Bus High Resistance	Intermittent communication	Corroded connector or damaged wiring	Perform resistance/voltage-drop tests and repair
354	CAN Bus Intermittent Short	Random warning lights	Harness chafing or damaged connector	Inspect harness and isolate short
355	LIN Bus Master Fault	Several body functions unavailable	Master ECU or communication fault	Check LIN master power, ground, and communication
356	LIN Bus Slave Fault	One body component unavailable	Slave module, wiring,ing or component fault	Test LIN signal and slave module
357	Automotive Ethernet Communication Fault	ADAS/infotainment functions unavailable	Cable, connector or module fault	Test Ethernet link and module communication
358	Network Termination Fault	Communication instability	Incorrect/missing termination	Check network termination according to vehicle specification
359	ECU Wake-Up Fault	Module remains asleep	Wake-up signal/network fault	Check wake-up line and network activity
360	ECU Sleep-Mode Fault	Battery drains overnight	Module fails to enter sleep mode	Monitor parasitic current and identify active module
361	Gateway Power Supply Fault	Many systems unavailable	Fuse, relay, or power wiring fault	Verify gateway power and ground
362	ECU Ground Voltage Drop	Intermittent ECU faults	High-resistance ground	Perform ground-side voltage-drop test and repair
363	ECU 5V Reference Short	Several sensor DTCs	Sensor or wiring shorting reference supply	Isolate sensors one by one and repair affected circuit
364	ECU 5V Reference Open	Multiple sensors malfunction	Broken reference wire or ECU fault	Check reference circuit and continuity
365	ECU Ignition Feed Fault	ECU does not wake up	Ignition relay/fuse/wiring fault	Test ignition feed and relay
366	Body Control Module Software Fault	Locks/lights/windows malfunction	Software corruption or configuration issue	Perform approved software update/configuration
367	Body Control Module Configuration Error	Functions incorrectly configured	Incorrect coding/programming	Restore correct vehicle configuration
368	Door Control Module Fault	Window/lock/mirror functions unavailable	Module power, ground, or internal fault	Test module supply and communication
369	Window Control Module Calibration Lost	Auto window function unavailable	Battery disconnection/module reset	Perform window initialization
370	Sunroof Calibration Lost	Sunroof reverses/stops incorrectly	Lost position calibration	Perform manufacturer-specified initialization
371	Power Tailgate Motor Fault	Tailgate won’t open/close	Motor, wiring, or control-module fault	Test motor and control circuit
372	Power Tailgate Position Sensor Fault	Tailgate stops incorrectly	Position sensor or wiring fault	Test sensor and perform calibration
373	Hands-Free Tailgate Sensor Fault	Foot sensor doesn’t work	Sensor, wiring or module fault	Inspect sensor and control circuit
374	Fuel Filler Door Actuator Fault	Fuel door won’t open/lock	Actuator, fuse or wiring fault	Test actuator and repair circuit
375	Trunk Lock Actuator Fault	Trunk won’t lock/unlock	Actuator or wiring fault	Test actuator and replace if necessary
376	Trunk Position Switch Fault	Trunk-open warning remains ON	Switch or wiring fault	Test switch status and wiring
377	Hood Position Sensor Fault	Hood-open warning/alarm issue	Sensor or wiring fault	Inspect and test hood switch
378	Door Position Sensor Fault	Door-open warning remains ON	Door latch sensor failure	Diagnose latch sensor and wiring
379	Seat Memory Module Communication Fault	Saved seat positions unavailable	CAN/LIN or module fault	Check power and communication
380	Power Seat Motor Short Circuit	Seat movement stops/blows fuse	Motor or wiring short	Check motor current and circuit
381	Seat Occupancy Sensor Fault	Passenger-airbag warning	Sensor, connector or module fault	Scan SRS and diagnose sensor circuit
382	Seatbelt Buckle Switch Fault	Seatbelt warning remains ON	Switch or wiring fault	Test buckle switch and circuit
383	Seatbelt Reminder System Fault	Reminder doesn’t operate correctly	Sensor, module or communication fault	Diagnose restraint system
384	Steering Wheel Switch Fault	Audio/cruise buttons unavailable	Switch, clockspring or wiring fault	Test switch signals and wiring
385	Steering Wheel Clockspring Fault	Horn/airbag/buttons fail	Damaged clockspring	Diagnose and replace according to SRS procedure
386	Horn Switch Circuit Fault	Horn doesn’t operate	Switch, clockspring or wiring fault	Check switch and control circuit
387	Cruise Control Switch Fault	Cruise control unavailable	Switch or wiring failure	Test switch signals and cruise-control circuit
388	Cruise Control Brake Input Fault	Cruise won’t activate	Brake-switch signal incorrect	Check brake switch adjustment and signal
389	Adaptive Cruise Control Radar Blockage	ACC unavailable	Di,rt, snow or obstruction	Clean radar area and verify system operation
390	ADAS Radar Heating Fault	Radar unavailable in cold conditions	Heater circuit failure	Test radar heater power and wiring
391	Front Camera Obstruction Detection Fault	Lane functions disabled	Dirt, fog or windshield obstruction	Clean camera viewing area and verify
392	Camera Lens Heating Fault	Camera image degraded	Heater failure	Test camera heater circuit
393	Parking Camera Wiring Fault	Intermittent camera image	Damaged video/network wiring	Inspect wiring and connectors
394	Surround-View Camera Calibration Fault	Misaligned 360° image	Calibration lost, or camera moved	Perform approved camera calibration
395	Rear Radar Communication Fault	Rear safety functions unavailable	CAN/Ethernet/power fault	Check radar power and network
396	Blind-Spot Indicator Failure	Mirror warning lamp doesn’t illuminate	LED, wiring or control fault	Test indicator and communication
397	Lane Assist Steering Communication Fault	Lane correction unavailable	ADAS-EPS communication fault	Check CAN/network and EPS status
398	AEB Brake Intervention Communication Fault	Automatic braking unavailable	ADAS/ABS communication issue	Scan both systems and repair network fault
399	ESC Engine-Torque Communication Fault	ESC/traction warning	CAN communication between ESC and ECU	Check network messages and affected modules
400	Vehicle Speed Network Signal Fault	Speed-dependent systems malfunction	Missing/incorrect vehicle-speed message	Trace wheel-speed/ABS source and CAN communication

No.	Auto Electric Problem	Common Symptoms	Possible Causes	Solution / Repair
401	Electric Parking Brake Module Communication Fault	EPB warning appears	CAN communication or module power fault	Check EPB power, ground, and CAN communication
402	EPB Position Sensor Fault	Parking brake position incorrect	Sensor or wiring failure	Test position feedback and replace faulty component
403	ABS ECU Internal Fault	ABS/ESC warning remains ON	Internal module failure	Verify power,r ground, and CAN before module replacement
404	ABS ECU Coding Error	ABS functions unavailable after replacement	Incorrect coding/configuration	Program/coding according to vehicle specification
405	ABS Hydraulic Unit Motor Fault	ABS pump warning	Pump motor or electrical circuit fault	Test motor power/current and replace unit if required
406	Wheel-Speed Sensor Air Gap Incorrect	Intermittent ABS/ESC warning	Incorrect sensor installation or damaged bearing/tone ring	Inspect sensor gap and wheel hub
407	Wheel-Speed Tone Ring Damage	Erratic wheel-speed signal	Cracked/corroded tone ring	Inspect and replace damaged ring/hub
408	Brake Pressure Sensor Calibration Fault	ESC/ABS warning	Lost calibration or incorrect sensor value	Perform specified calibration
409	Yaw Sensor Calibration Lost	ESC warning after alignment/repair	Calibration data lost	Perform yaw-rate sensor calibration
410	Steering Angle Sensor Calibration Lost	Steering/ESC warning	Alignment or battery/module reset	Perform steering-angle calibration
411	TPMS Receiver Fault	All/most tire pressures unavailable	Receiver power or communication fault	Check receiver power, ground, and network
412	TPMS Sensor Not Registered	One tire pressure not displayed	New sensor not learned	Register/learn the sensor
413	TPMS Sensor Signal Weak	Intermittent tire-pressure reading	Sensor battery/antenna issue	Test sensor and replace if necessary
414	TPMS Antenna Fault	Sensors cannot be detected	Damaged antenna/wiring	Inspect antenna and wiring
415	Airbag ECU Power Supply Fault	SRS warning/no communication	Fuse, relay wiring, or ground fault	Verify SRS module power and ground
416	SRS Communication Fault	Airbag warning remains ON	CAN wiring or module fault	Scan SRS and check network communication
417	Crash Sensor Communication Fault	SRS DTC	Sensor/network/wiring fault	Check sensor power, ground, and communication
418	Airbag Connector Poor Contact	Intermittent SRS warning	Loose/corroded connector	Inspect connector and repair using approved SRS procedure
419	Passenger Airbag Deactivation Indicator Fault	Passenger-airbag status incorrect	Indicator, wiring or SRS module fault	Diagnose SRS system
420	Seatbelt Pretensioner Circuit Open	SRS warning	Broken wiring/connector	Diagnose and repair according to manufacturer procedure
421	Electric Power Steering Power Supply Fault	Heavy steering	Fuse, relay, battery, or wiring fault	Check EPS power and ground
422	EPS CAN Communication Fault	EPS/ESC warnings	CAN wiring or module fault	Test CAN network and EPS module
423	EPS Torque Sensor Calibration Fault	Uneven steering assistance	Calibration lost	Perform approved calibration
424	EPS Motor Overcurrent Fault	Steering assistance cuts out	Mechanical resistance or motor fault	Check steering mechanism and motor current
425	Active Suspension Height Sensor Fault	Vehicle height warning	Sensor/linkage/wiring fault	Inspect sensor and linkage; calibrate if required
426	Suspension Compressor Fault	Vehicle won’t raise/lower	Compressor, relay or wiring fault	Check compressor power and pressure system
427	Air Suspension Solenoid Fault	Uneven vehicle height	Solenoid or control circuit fault	Test solenoid and wiring
428	Adaptive Damper Communication Fault	Suspension warning	CAN/LIN or damper module fault	Check network and damper control
429	Electronic Differential Control Fault	Traction/handling problem	Actuator, sensor or module fault	Scan system and test actuator
430	Active Torque Vectoring Fault	Reduced cornering performance	Motor/actuator/network fault	Diagnose torque-vectoring system
431	Regenerative Braking Communication Fault	Reduced energy recovery	BMS/inverter/ABS communication fault	Check high-voltage system communication
432	Brake-by-Wire System Fault	Brake warning/reduced function	Control module, sensor or actuator fault	Follow manufacturer safety procedure and diagnose system
433	Brake Pedal Position Sensor Fault	Brake-control warning	Sensor or wiring fault	Test dual-channel pedal signal
434	Brake Booster Electric Pump Fault	Hard brake pedal	Pump, relay, fuse or wiring fault	Test pump operation and power supply
435	Electronic Brake Booster Communication Fault	Brake warning	CAN/network or module fault	Check power, ground and communication
436	Hybrid Brake Control Fault	Hybrid brake warning	Brake ECU, sensors or communication fault	Scan hybrid brake system and diagnose root cause
437	High-Voltage Interlock Fault	EV/Hybrid won’t enter READY mode	Open interlock circuit/connector	Inspect HV interlock circuit using approved safety procedures
438	High-Voltage Battery Service Disconnect Fault	Vehicle won’t start/charge	Disconnect not installed correctly	Inspect and secure according to manufacturer procedure
439	High-Voltage Battery Cooling Fan Fault	Battery temperature warning	Fan, fuse or control fault	Test cooling fan and control circuit
440	High-Voltage Battery Temperature Sensor Fault	Battery warning/reduced power	Sensor or wiring failure	Diagnose sensor circuit
441	Battery Management System Communication Fault	EV/hybrid warning	CAN communication or BMS fault	Check BMS power, ground, and network
442	BMS State-of-Charge Sensor Fault	Incorrect battery percentage	Current/voltage sensing problem	Diagnose BMS sensing circuits
443	DC-DC Converter Fault	12V battery not charging in EV/hybrid	Converter or control circuit fault	Diagnose converter and low-voltage charging circuit
444	Inverter Communication Fault	EV/hybrid propulsion warning	CAN/network or inverter fault	Check communication, power and ground
445	Electric Traction Motor Position Sensor Fault	Reduced power/drive warning	Resolver/position sensor or wiring fault	Diagnose motor position feedback
446	EV Charging Port Lock Fault	Charging connector won’t lock	Lock actuator/sensor/wiring fault	Test charging-port lock circuit
447	On-Board Charger Fault	AC charging unavailable	Charger, power supply or communication fault	Diagnose charger using manufacturer procedure
448	EV Charging Communication Fault	Charging fails to start	Pilot/proximity circuit or charger communication fault	Inspect charging communication circuit
449	High-Voltage Isolation Fault	HV warning/vehicle won’t enter READY	Insulation resistance below specification	Stop operation and perform manufacturer-approved HV isolation diagnosis
450	High-Voltage System Ground Fault	HV warning/reduced operation	Insulation or grounding problem	Isolate the fault using approved high-voltage safety procedures

No.	Auto Electric Problem	Common Symptoms	Possible Causes	Solution / Repair
451	High-Voltage Battery Cell Imbalance	Reduced EV range/power	Cell voltage imbalance or aging	Diagnose cell voltages with approved equipment; service/replace battery as specified.
452	High-Voltage Battery Cell Voltage Sensor Fault	HV battery warning	Sensor/BMS wiring fault	Diagnose BMS sensing circuit
453	High-Voltage Battery Pack Overtemperature	Power reduction/warning	Cooling failure, high load, or battery fault	Check cooling system and battery temperature data
454	High-Voltage Battery Pack Undertemperature	Reduced charging/performance	Very low battery temperature	Check battery thermal-management system
455	Battery Cooling Pump Fault	HV battery temperature rises	Pump motor, fuse or wiring fault	Test pump power, ground and control
456	Battery Cooling Valve Fault	Incorrect battery temperature	Valve actuator or control fault	Test valve operation and wiring
457	Battery Cooling Fan Fault	Battery overheating	Fan motor, relay or controller fault	Check fan circuit and airflow
458	Battery Heater Fault	Slow charging in cold conditions	Heater, relay or control fault	Diagnose battery-heater circuit
459	HV Battery Contactor Fault	EV won’t enter READY	Contactor coil, wiring or BMS fault	Diagnose contactor control circuit using HV safety procedures
460	Pre-Charge Circuit Fault	HV system won’t initialize	Pre-charge resistor, relay or wiring fault	Diagnose pre-charge circuit according to manufacturer procedure
461	HV Contactor Welded Contacts	HV remains energized unexpectedly	Contactor contacts welded	Isolate HV system and replace defective contactor
462	HV Contactor Coil Open Circuit	Vehicle won’t enter READY	Open coil/wiring	Test control circuit and replace contactor if required
463	HV Interlock Circuit Open	EV/hybrid system disabled	Loose connector/service disconnect	Inspect interlock loop using approved procedures
464	HV Service Plug Detection Fault	HV warning/no READY	Service plug sensor or connection fault	Verify installation and detection circuit
465	Inverter Cooling Pump Fault	Reduced EV power	Pump or control circuit failure	Check inverter cooling system
466	Inverter Overtemperature Fault	Power reduction	Cooling problem or excessive load	Check coolant flow, temperature, and inverter system
467	Traction Inverter Power Supply Fault	Motor doesn’t operate	HV supply, contactor, or wiring fault	Diagnose HV supply and inverter
468	Traction Motor Resolver Fault	Motor warning/limited power	Resolver or wiring fault	Test position-feedback circuit
469	Traction Motor Overtemperature Sensor Fault	Reduced power	Temperature sensor/wiring fault	Check sensor data and circuit
470	EV Motor Phase Wiring Fault	Motor vibration/no drive	Damaged phase cable/connection	Inspect phase connections under approved HV procedures
471	EV Motor Phase Current Sensor Fault	Power limitation	Current sensor or inverter fault	Diagnose current-sensing circuit
472	Electric Motor Stator Insulation Fault	HV isolation warning	Insulation breakdown	Perform approved insulation testing
473	HV Cable Insulation Damage	Isolation warning	Damaged HV cable insulation	Isolate HV system and replace damaged cable
474	HV Connector Poor Contact	Intermittent HV fault	Loose/corroded connector	Inspect and repair according to HV procedures
475	HV Connector Lock Detection Fault	Vehicle won’t enter READY	Connector lock sensor fault	Inspect locking mechanism and detection circuit
476	DC Fast-Charging Failure	DC charging won’t start	Charger, communication or HV-system fault	Diagnose charging system and communication
477	AC Charging Failure	Home/AC charging unavailable	On-board charger, pilot circuit or supply fault	Check charger input and communication
478	Charging Pilot Signal Fault	Charging session won’t initiate	Pilot circuit/wiring problem	Test pilot signal according to manufacturer specification
479	Charging Proximity Signal Fault	Charging connector not recognized	Proximity circuit or connector fault	Check proximity circuit and connector
480	Charging Port Temperature Sensor Fault	Charging power reduced/stopped	Sensor or wiring fault	Test port temperature circuit
481	Charging Port Overtemperature	Charging stops unexpectedly	High contact resistance or excessive current	Inspect connector and charging-port contacts
482	Charging Cable Detection Fault	Charger not recognized	Cable/connector detection problem	Test cable detection circuit
483	Charging Door Actuator Fault	Charging dooron’topen,	Actuat or fuse or wiring fault	Test actuator and control circuit
484	On-Board Charger Cooling Fault	Charging stops/reduces	Cooling pump/fan or temperature issue	Diagnose charger thermal-management system
485	DC-DC Converter Overtemperature	12V charging stops	Cooling problem or excessive load	Check converter cooling and electrical load
486	12V Battery Charging Fault in EV	12V battery becomes discharged	DC-DC converter or wiring fault	Test converter output and low-voltage circuit
487	12V Battery Monitoring Fault in EV	Battery-management warning	Sensor or communication fault	Check battery sensor and network
488	HV System Pre-Charge Voltage Fault	READY mode unavailable	Pre-charge circuit or voltage-sensing fault	Diagnose pre-charge and voltage feedback
489	HV Bus Voltage Sensor Fault	Inverter/HV warning	Voltage sensor or wiring fault	Test HV voltage-sensing circuit safely
490	Inverter DC-Link Capacitor Fault	Inverter warning/no drive	Capacitor degradation or electrical fault	Diagnose inverter according to manufacturer procedure
491	Electric A/C Compressor Communication Fault	A/C unavailable	CAN/LIN communication or compressor controller fault	Check communication, power and ground
492	Electric A/C Compressor Insulation Fault	HV isolation/A/C warning	Internal insulation breakdown	Stop operation and perform approved insulation diagnosis
493	PTC Cabin Heater Fault	Cabin heating unavailable	Heater element, relay/controller or HV fault	Diagnose heater circuit using HV safety procedures
494	PTC Heater Overtemperature Fault	Heater shuts down	Thermal sensor/cooling problem	Check temperature sensing and thermal management
495	Heat Pump Control Fault	Poor cabin heating/range	Valve, sensor, or controller fault	Diagnose heat-pump system
496	HVAC Control Module Communication Fault	Climate controls malfunction	CAN/LIN/module fault	Check module power and network
497	Electric Refrigerant Valve Fault	A/C/heat-pump performance poor	Electronic expansion valve/actuator fault	Test valve command and feedback
498	Cabin Air Quality Sensor Fault	Automatic ventilation behaves incorrectly	Sensor or wiring fault	Test sensor and circuit
499	HVAC Sunload Sensor Fault	Automatic climate control inaccurate	Sensor or wiring problem	Check sensor signal and replace if required
500	Vehicle Thermal Management Communication Fault	Multiple heating/cooling warnings	CAN/LIN/network or control-module fault	Scan thermal-management modules and repair communication fault