OBD-II fault codes with plain-word explanations
What every fault code means and where to start checking. 298 codes, the same reference the app uses.
Every one of the 298 codes has a where-to-start guide, not just a definition.
Or browse the powertrain codes by system
Powertrain 249
P0010Intake camshaft actuator (bank 1) — circuit malfunctionP0011Intake camshaft position (bank 1) — timing over-advanced or system performanceP0012Intake camshaft timing (bank 1) — over-retardedP0013Exhaust camshaft actuator (bank 1) — circuit malfunctionP0014Exhaust camshaft position (bank 1) — timing over-advanced or system performanceP0015Exhaust camshaft timing (bank 1) — over-retardedP0016Crankshaft/camshaft position correlation (bank 1, intake)P0017Crankshaft/camshaft position correlation (bank 1, exhaust)P0020Intake camshaft actuator (bank 2) — circuit malfunctionP0021Intake camshaft timing (bank 2) — over-advancedP0022Intake camshaft timing (bank 2) — over-retardedP0024Exhaust camshaft timing (bank 2) — over-advancedP0030O2 sensor heater circuit malfunction (bank 1, sensor 1)P0037O2 sensor heater circuit low (bank 1, sensor 2)P0087Fuel rail pressure too lowP0088Fuel rail pressure too highP0089Fuel pressure regulator performanceP0096Intake air temperature sensor 2 circuit range/performanceP0100Mass air flow circuit malfunctionP0101Mass air flow circuit range/performanceP0102Mass air flow circuit low inputP0103Mass air flow circuit high inputP0106Manifold absolute pressure circuit range/performanceP0107Manifold absolute pressure circuit low inputP0108Manifold absolute pressure circuit high inputP0111Intake air temperature circuit range/performanceP0112Intake air temperature circuit low inputP0113Intake air temperature circuit high inputP0116Engine coolant temperature circuit range/performanceP0117Engine coolant temperature circuit low inputP0118Engine coolant temperature circuit high inputP0121Throttle position sensor A circuit range/performanceP0122Throttle position sensor A circuit low inputP0123Throttle position sensor A circuit high inputP0128Coolant thermostat — temperature below regulating temperatureP0130Upstream O2 sensor circuit malfunction (bank 1)P0131Upstream O2 sensor circuit low voltage (bank 1)P0132Upstream O2 sensor circuit high voltage (bank 1)P0133Upstream O2 sensor slow response (bank 1) — usually a worn sensorP0134Upstream O2 sensor no activity (bank 1) — open circuit or burnt sensorP0135O2 sensor heater circuit malfunction (bank 1, upstream)P0136Downstream O2 sensor circuit malfunction (bank 1)P0137Downstream O2 sensor circuit low voltage (bank 1)P0138Downstream O2 sensor circuit high voltage (bank 1)P0139Downstream O2 sensor slow response (bank 1)P0140Downstream O2 sensor no activity detected (bank 1)P0141O2 sensor heater circuit malfunction (bank 1, downstream)P0143O2 sensor circuit low voltage (bank 1, sensor 3)P0150Upstream O2 sensor circuit malfunction (bank 2)P0155O2 sensor heater circuit malfunction (bank 2, upstream)P0161O2 sensor heater circuit malfunction (bank 2, downstream)P0171System too lean (bank 1) — air leak or not enough fuelP0172System too rich (bank 1)P0174System too lean (bank 2)P0175System too rich (bank 2)P0190Fuel rail pressure sensor — malfunctionP0191Fuel rail pressure sensor — reading out of rangeP0193Fuel rail pressure sensor — high signalP0201Injector circuit malfunction — cylinder 1P0202Injector circuit malfunction — cylinder 2P0203Injector circuit malfunction — cylinder 3P0204Injector circuit malfunction — cylinder 4P0217Engine overheatingP0221Throttle position sensor B circuit range/performanceP0230Fuel pump primary circuit — malfunctionP0231Fuel pump secondary circuit — low signalP0234Turbocharger boost pressure too highP0235Turbocharger boost sensor — malfunctionP0236Turbocharger boost sensor — reading out of rangeP0238Turbocharger boost sensor — high signalP0243Turbocharger wastegate solenoid — circuit malfunctionP0245Turbocharger wastegate solenoid — low signalP0246Turbocharger wastegate solenoid — high signalP0251Injection pump metering unit — malfunctionP0261Injector 1 — circuit shorted to groundP0262Injector 1 — circuit shorted to powerP0263Cylinder 1 — contribution or balance faultP0299Turbocharger boost pressure too lowP0300Random/multiple cylinder misfire detectedP0301Cylinder 1 misfire detectedP0302Cylinder 2 misfire detectedP0303Cylinder 3 misfire detectedP0304Cylinder 4 misfire detectedP0305Cylinder 5 misfire detectedP0306Cylinder 6 misfire detectedP0313Misfire detected with low fuel levelP0315Crankshaft position variation not learnedP0324Knock sensor system errorP0325Knock sensor circuit malfunctionP0326Knock sensor (bank 1) — signal out of rangeP0327Knock sensor (bank 1) — low signalP0328Knock sensor (bank 1) — high signalP0330Knock sensor (bank 2) — malfunctionP0335Crankshaft position sensor circuit malfunctionP0336Crankshaft position sensor circuit range/performanceP0340Camshaft position sensor circuit malfunctionP0341Camshaft position sensor circuit range/performanceP0350Ignition coil — circuit malfunctionP0351Ignition coil, cylinder 1 — circuit malfunctionP0352Ignition coil, cylinder 2 — circuit malfunctionP0353Ignition coil, cylinder 3 — circuit malfunctionP0354Ignition coil, cylinder 4 — circuit malfunctionP0355Ignition coil, cylinder 5 — circuit malfunctionP0356Ignition coil, cylinder 6 — circuit malfunctionP0363Misfire detected — fuelling disabledP0380Glow plug circuit — malfunctionP0381Glow plug indicator lamp — circuit malfunctionP0400Exhaust gas recirculation (EGR) — malfunctionP0401EGR flow insufficient detectedP0402EGR flow excessive detectedP0403EGR valve — control circuit malfunctionP0404EGR valve — position out of range, stickingP0405EGR position sensor — low signalP0409EGR position sensor — circuit malfunctionP0410Secondary air injection system — malfunctionP0411Secondary air injection — incorrect flowP0412Secondary air valve — circuit malfunctionP0420Catalyst system efficiency below threshold (bank 1)P0421Warm-up catalyst efficiency below limit (bank 1)P0430Catalyst efficiency below limit (bank 2)P0431Warm-up catalyst efficiency below limit (bank 2)P0440Evaporative emission system — malfunctionP0441Evaporative emission system purge flow faultP0442Evaporative emission system leak detected (small leak)P0443Evaporative emission purge control valve circuit malfunctionP0444Canister purge valve — open circuitP0446Canister vent valve — circuit malfunctionP0447Canister vent valve — open circuitP0448Canister vent valve — circuit shortedP0449Canister vent valve — control malfunctionP0450Fuel vapour pressure sensor — malfunctionP0451Fuel vapour pressure sensor — reading out of rangeP0452Fuel vapour pressure sensor — low signalP0453Fuel vapour pressure sensor — high signalP0455Evaporative emission system leak detected (gross leak)P0456Evaporative emission system leak detected (very small leak)P0457Evaporative leak — fuel cap left looseP0460Fuel level sensor — malfunctionP0461Fuel level sensor — reading out of rangeP0462Fuel level sensor — low signalP0463Fuel level sensor — high signalP0480Cooling fan 1 control circuit malfunctionP0500Vehicle speed sensor malfunctionP0501Vehicle speed sensor — reading out of rangeP0502Vehicle speed sensor — low signalP0504Brake switch — signal mismatchP0505Idle air control system malfunctionP0506Idle speed lower than expectedP0507Idle speed higher than expectedP0508Idle air control — low signalP050ACold start idle control system performanceP0513Immobiliser — invalid keyP0520Engine oil pressure sensor circuit malfunctionP0521Oil pressure sensor — reading out of rangeP0522Oil pressure sensor — low signalP0523Oil pressure sensor — high signalP0524Engine oil pressure too lowP0544Exhaust gas temperature sensor (bank 1) — circuit malfunctionP0560System voltage — malfunctionP0561System voltage unstableP0562System voltage lowP0563System voltage highP0571Brake switch circuit malfunctionP0600Internal control module communication errorP0601Internal control module memory errorP0603Internal control module keep alive memory errorP0605Internal control module ROM errorP0606Internal control module processor errorP0620Generator control circuit — malfunctionP0621Generator lamp — circuit malfunctionP0622Generator field terminal — circuit malfunctionP0625Generator field terminal — low signalP0626Generator field terminal — high signalP0627Fuel pump relay — circuit malfunctionP0628Fuel pump relay — low signalP0629Fuel pump relay — high signalP062FControl module non-volatile memory errorP0630VIN not programmed or mismatchP0645A/C clutch relay — circuit malfunctionP0650Malfunction indicator lamp — circuit faultP0685ECU main relay — circuit malfunctionP0691Cooling fan relay — low signalP0692Cooling fan relay — high signalP0693Cooling fan relay 2 — low signalP0700Transmission control module fault — check transmission codesP0701Transmission control system — malfunctionP0705Transmission range sensor circuit malfunctionP0710Transmission fluid temperature sensor — malfunctionP0711Transmission fluid temperature sensor circuit range/performanceP0715Input speed sensor — malfunctionP0717Input speed sensor — no signalP0720Output speed sensor — malfunctionP0725Engine speed input to transmission — malfunctionP0730Incorrect gear ratioP0741Torque converter clutch slippingP0743Torque converter clutch — circuit malfunctionP0750Shift solenoid A — malfunctionP0751Shift solenoid A — stuckP0755Shift solenoid B — malfunctionP0756Shift solenoid B — stuckP0850Park/neutral switch circuit malfunctionP1000Self-test not completed — a full drive cycle is neededP2002Diesel particulate filter efficiency below limit (bank 1)P2003Diesel particulate filter efficiency below limit (bank 2)P2004Intake manifold runner control stuck open (bank 1)P2006Intake manifold runner control stuck closed (bank 1)P2008Intake manifold runner control — circuit malfunctionP2015Intake manifold runner position sensor — malfunctionP2032Exhaust gas temperature sensor 3 — low signalP203BReductant level sensor — malfunctionP2047Reductant injector — circuit malfunctionP2048Reductant injector — low signalP204FReductant system performance below limitP2096System too lean off idle (bank 1)P2097System too rich off idle (bank 1)P20EESCR catalyst efficiency below limit (bank 1)P2100Throttle actuator — circuit openP2101Throttle actuator — range or performance faultP2102Throttle actuator — circuit lowP2103Throttle actuator — circuit highP2110Throttle actuator — forced limited RPMP2119Throttle body — sticking, position mismatchP2122Accelerator pedal sensor D — low signalP2123Accelerator pedal sensor D — high signalP2127Accelerator pedal sensor E — low signalP2128Accelerator pedal sensor E — high signalP2135Throttle position sensors A and B — correlation faultP2138Accelerator pedal sensors D and E — correlation faultP2177System too lean off idle (bank 1)P2178System too rich off idle (bank 1)P2179System too lean off idle (bank 2)P2180System too rich off idle (bank 2)P2187System too lean at idle (bank 1)P2188System too rich at idle (bank 1)P2189System too lean at idle (bank 2)P2195Oxygen sensor (bank 1, upstream) — signal stuck leanP2196Oxygen sensor (bank 1, upstream) — signal stuck richP2197Oxygen sensor (bank 2, upstream) — signal stuck leanP2200NOx sensor (bank 1) — circuit malfunctionP2201NOx sensor (bank 1) — reading out of rangeP2263Turbocharger boost system performanceP2270O2 sensor signal stuck lean (bank 1, sensor 2)P2271O2 sensor signal stuck rich (bank 1, sensor 2)P2453DPF differential pressure sensor — malfunctionP2454DPF differential pressure sensor — low signalP2455DPF differential pressure sensor — high signalP2458DPF regeneration duration faultP2459DPF regeneration frequency faultP2463DPF — excessive soot accumulation
Chassis 17
C0031Left front wheel speed sensor malfunctionC0034Right front wheel speed sensor malfunctionC0035Wheel speed sensor — the number is read differentlyC0037Left rear wheel speed sensor malfunctionC003ARight rear wheel speed sensor malfunctionC0040C0040: brake pedal switch in the standard, front right wheel at GMC0044Lateral acceleration sensor malfunctionC0045Wheel speed sensor — no signal (rear left at GM)C0050Wheel speed mismatch (rear right wheel at GM)C0051Steering angle sensor malfunctionC0061ABS hydraulic unit valve malfunctionC0110ABS pump motor circuit malfunctionC0121ABS valve circuit malfunctionC0196Yaw rate sensor malfunctionC0561Stability control disabled by another moduleC1095ABS pump motor does not reach operating modeC1145Wheel speed sensor — intermittent signal, usually a corroded connector
Body 12
B1000Body control module internal errorB1001Control module not configured for this trimB1015Driver airbag circuit malfunctionB1016Passenger airbag circuit malfunctionB1025Seat belt pretensioner circuit malfunctionB1049Impact sensor circuit malfunctionB1055Seat belt buckle switch circuit malfunctionB1200Climate control module — air door malfunctionB1318Control module supply voltage lowB1342Module has failed and must be replacedB2103Exterior lighting circuit malfunctionB2205Control module programming compatibility error
Network 20
U0001High speed CAN bus — general malfunctionU0073CAN bus off — module went into protectionU0074Second CAN bus — no communicationU0100Lost communication with engine control moduleU0101Lost communication with transmission control moduleU0121Lost communication with ABS/ESP moduleU0122Lost communication with stability control moduleU0126Lost communication with steering angle sensorU0131Lost communication with electric power steeringU0140Lost communication with body control module (BCM)U0151Lost communication with airbag control moduleU0155Lost communication with instrument clusterU0159Lost communication with parking sensorsU0164Lost communication with climate control moduleU0167Lost communication with immobiliserU0184Lost communication with radio/infotainmentU0401Invalid data from engine control moduleU0415Invalid data from ABS moduleU0416Invalid data from stability control moduleU0422Invalid data from body control module