Car fault codes, explained in plain words
What the code means, how urgent it is, and what to check first.
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Fuel pressure
Mass air flow (MAF) sensor
Manifold pressure (MAP) sensor
Intake air temperature sensor
Coolant temperature sensor
Throttle / pedal position sensor
Engine not warming up
Oxygen (O2 / lambda) sensor
- P0130 O2 Sensor Circuit (Bank 1 Sensor 1)
- P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
- P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
- P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
- P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
- P0135 O2 Sensor Heater Circuit (Bank 1 Sensor 1)
- P0136 O2 Sensor Circuit (Bank 1 Sensor 2)
- P0137 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)
- P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
- P0139 O2 Sensor Circuit Slow Response (Bank 1 Sensor 2)
- P0140 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)
- P0141 O2 Sensor Heater Circuit (Bank 1 Sensor 2)
- P0142 O2 Sensor Circuit (Bank 1 Sensor 3)
- P0143 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 3)
- P0144 O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)
- P0145 O2 Sensor Circuit Slow Response (Bank 1 Sensor 3)
- P0146 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 3)
- P0147 O2 Sensor Heater Circuit (Bank 1 Sensor 3)
- P0150 O2 Sensor Circuit (Bank 2 Sensor 1)
- P0151 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)
- P0152 O2 Sensor Circuit High Voltage (Bank 2 Sensor 1)
- P0153 O2 Sensor Circuit Slow Response (Bank 2 Sensor 1)
- P0154 O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)
- P0155 O2 Sensor Heater Circuit (Bank 2 Sensor 1)
- P0156 O2 Sensor Circuit (Bank 2 Sensor 2)
- P0157 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
- P0158 O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)
- P0159 O2 Sensor Circuit Slow Response (Bank 2 Sensor 2)
- P0160 O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)
- P0161 O2 Sensor Heater Circuit (Bank 2 Sensor 2)
- P0162 O2 Sensor Circuit (Bank 2 Sensor 3)
- P0163 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 3)
- P0164 O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)
- P0165 O2 Sensor Circuit Slow Response (Bank 2 Sensor 3)
- P0166 O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 3)
- P0167 O2 Sensor Heater Circuit (Bank 2 Sensor 3)
Fuel trim
Engine running lean
Engine running rich
Fuel injector circuit
- P0200 Injector Circuit/Open
- P0201 Injector Circuit/Open - Cylinder 1
- P0202 Injector Circuit/Open - Cylinder 2
- P0203 Injector Circuit/Open - Cylinder 3
- P0204 Injector Circuit/Open - Cylinder 4
- P0205 Injector Circuit/Open - Cylinder 5
- P0206 Injector Circuit/Open - Cylinder 6
- P0207 Injector Circuit/Open - Cylinder 7
- P0208 Injector Circuit/Open - Cylinder 8
- P0209 Injector Circuit/Open - Cylinder 9
- P0210 Injector Circuit/Open - Cylinder 10
- P0211 Injector Circuit/Open - Cylinder 11
- P0212 Injector Circuit/Open - Cylinder 12
Turbo underboost
Misfire
Misfire on one cylinder
- P0301 Cylinder 1 Misfire Detected
- P0302 Cylinder 2 Misfire Detected
- P0303 Cylinder 3 Misfire Detected
- P0304 Cylinder 4 Misfire Detected
- P0305 Cylinder 5 Misfire Detected
- P0306 Cylinder 6 Misfire Detected
- P0307 Cylinder 7 Misfire Detected
- P0308 Cylinder 8 Misfire Detected
- P0309 Cylinder 9 Misfire Detected
- P0310 Cylinder 10 Misfire Detected
- P0311 Cylinder 11 Misfire Detected
- P0312 Cylinder 12 Misfire Detected
Knock sensor
Crankshaft position sensor
Camshaft position sensor
Ignition coil circuit
- P0351 Ignition Coil "A" Primary/Secondary Circuit
- P0352 Ignition Coil "B" Primary/Secondary Circuit
- P0353 Ignition Coil "C" Primary/Secondary Circuit
- P0354 Ignition Coil "D" Primary/Secondary Circuit
- P0355 Ignition Coil "E" Primary/Secondary Circuit
- P0356 Ignition Coil "F" Primary/Secondary Circuit
- P0357 Ignition Coil "G" Primary/Secondary Circuit
- P0358 Ignition Coil "H" Primary/Secondary Circuit
- P0359 Ignition Coil "I" Primary/Secondary Circuit
- P0360 Ignition Coil "J" Primary/Secondary Circuit
- P0361 Ignition Coil "K" Primary/Secondary Circuit
- P0362 Ignition Coil "L" Primary/Secondary Circuit
EGR (exhaust gas recirculation)
Secondary air injection
Catalytic converter efficiency
EVAP (fuel vapour) system
- P0440 Evaporative Emission System
- P0441 Evaporative Emission System Incorrect Purge Flow
- P0442 Evaporative Emission System Leak Detected (Small Leak)
- P0443 Evaporative Emission System Purge Control Valve "A" Circuit
- P0446 Evaporative Emission System Vent Control Circuit
- P0455 Evaporative Emission System Leak Detected (Large Leak)
- P0456 Evaporative Emission System Leak Detected (Very Small Leak)
Cooling fan
Vehicle speed sensor
Idle speed control
System voltage
Transmission fault flag
Network communication
- U0001 High Speed CAN Communication Bus
- U0100 Lost Communication With ECM/PCM "A"
- U0101 Lost Communication With TCM
- U0121 Lost Communication With Anti-Lock Brake System (ABS) Control Module
- U0140 Lost Communication With Body Control Module
- U0155 Lost Communication With Instrument Panel Cluster (IPC) Control Module