OBD2 fault codes
What each generic OBD2 code means, in plain English: what the car has seen, why it usually happens, what you’ll notice and whether you can keep driving.
Most searched
- P0420 Catalytic converter efficiency below threshold (bank 1)
- P0300 Random or multiple cylinder misfire
- P0171 Mixture too lean (bank 1)
- P0299 Turbocharger or supercharger underboost
- P0401 Exhaust gas recirculation (EGR) flow insufficient
- P0101 Air flow sensor range or performance problem
- P0128 Thermostat: coolant not reaching normal operating temperature
- P0340 Camshaft position sensor A circuit fault (bank 1)
- P0335 Crankshaft position sensor A circuit fault
- P2002 Diesel particulate filter efficiency below threshold (bank 1)
- P0087 Fuel rail or system pressure too low
- P0234 Turbocharger or supercharger A overboost
- P0016 Crankshaft and camshaft position mismatch (bank 1, sensor A)
- P0113 Intake air temperature sensor circuit high
- P0442 EVAP system small leak detected
- P0455 EVAP system large leak detected
- P0500 Vehicle speed sensor malfunction
- P0562 System voltage low
- P0700 Transmission control system: fault detected
- U0100 Lost communication with engine control module (ECM/PCM A)
- P0301 Misfire detected in cylinder 1
- P0302 Misfire detected in cylinder 2
- P0303 Misfire detected in cylinder 3
- P0304 Misfire detected in cylinder 4
- P0172 System running too rich (bank 1)
- P0174 System running too lean (bank 2)
- P0102 Air flow sensor circuit low input
- P0380 Glow plug circuit A fault
- P2463 Diesel particulate filter restriction: soot accumulation
- P0606 ECM/PCM processor fault
How to read an OBD code
A fault code has a letter and four characters. The letter tells you which part of the car it comes from:
- P, powertrain: engine and gearbox.
- C, chassis: brakes, ABS, steering and suspension.
- B, body: airbag, locking, climate control and lights.
- U, the communication network between control units.
The first digit tells you who defines it. 0 is generic: it’s set by the SAE J2012 standard and means the same on any make, and so are P2xxx, P34xx and U0xxx codes. 1 belongs to the manufacturer, and each make uses it its own way. The rest points to the system and the specific fault: among P0 codes, for example, P03xx is ignition and P04xx is emissions control.
Here you’ll find every generic engine and network code explained in our own words. To read the ones on your car you need an OBD2 scanner and an app; how to do it is in the guide to reading and clearing fault codes.
All codes explained
The most searched codes, sorted by group.
P00xx: Air, fuel and emissions
- P0010 Camshaft A actuator control: open circuit (bank 1)
- P0011 Camshaft A timing over-advanced (bank 1)
- P0012 Camshaft A timing over-retarded (bank 1)
- P0013 Camshaft B actuator control: open circuit (bank 1)
- P0014 Camshaft B timing over-advanced (bank 1)
- P0015 Camshaft B timing over-retarded (bank 1)
- P0016 Crankshaft and camshaft position mismatch (bank 1, sensor A)
- P0017 Crankshaft and camshaft position mismatch (bank 1, sensor B)
- P0018 Crankshaft and camshaft position mismatch (bank 2, sensor A)
- P0019 Crankshaft and camshaft position mismatch (bank 2, sensor B)
- P0020 Camshaft A actuator control: open circuit (bank 2)
- P0021 Camshaft A timing over-advanced (bank 2)
- P0022 Camshaft A timing over-retarded (bank 2)
- P0030 Oxygen sensor heater circuit fault (bank 1, sensor 1)
- P0031 Oxygen sensor heater circuit low (bank 1, sensor 1)
- P0032 Oxygen sensor heater circuit high (bank 1, sensor 1)
- P0036 Oxygen sensor heater circuit fault (bank 1, sensor 2)
- P0037 Oxygen sensor heater circuit low (bank 1, sensor 2)
- P0038 Oxygen sensor heater circuit high (bank 1, sensor 2)
- P0045 Boost control solenoid: open circuit
- P0046 Boost control solenoid: range or performance
- P0047 Boost control solenoid: circuit low
- P0048 Boost control solenoid: circuit high
- P0049 Turbocharger or supercharger turbine overspeed
- P0050 Oxygen sensor heater circuit fault (bank 2, sensor 1)
- P0051 Oxygen sensor heater circuit low (bank 2, sensor 1)
- P0052 Oxygen sensor heater circuit high (bank 2, sensor 1)
- P0056 Oxygen sensor heater circuit fault (bank 2, sensor 2)
- P0057 Oxygen sensor heater circuit low (bank 2, sensor 2)
- P0058 Oxygen sensor heater circuit high (bank 2, sensor 2)
- P0069 Manifold pressure and barometric pressure do not match
- P0070 Ambient air temperature sensor circuit fault
- P0071 Ambient air temperature sensor range or performance problem
- P0087 Fuel rail or system pressure too low
- P0088 Fuel rail or system pressure too high
- P0089 Fuel pressure regulator performance problem
- P0090 Fuel pressure regulator control circuit fault
- P0091 Fuel pressure regulator control circuit low
- P0092 Fuel pressure regulator control circuit high
- P0093 Large leak detected in the fuel system
P01xx: Air and fuel metering
- P0100 Mass or volume air flow sensor circuit fault
- P0101 Air flow sensor range or performance problem
- P0102 Air flow sensor circuit low input
- P0103 Air flow sensor circuit high input
- P0104 Air flow sensor circuit intermittent
- P0105 Manifold absolute pressure (MAP) sensor circuit fault
- P0106 Manifold absolute pressure (MAP) sensor range or performance
- P0107 Manifold absolute pressure (MAP) sensor circuit low
- P0108 Manifold absolute pressure (MAP) sensor circuit high
- P0109 Manifold absolute pressure (MAP) sensor circuit intermittent
- P0110 Intake air temperature sensor circuit fault
- P0111 Intake air temperature sensor range or performance
- P0112 Intake air temperature sensor circuit low
- P0113 Intake air temperature sensor circuit high
- P0114 Intake air temperature sensor circuit intermittent
- P0115 Engine coolant temperature sensor circuit fault
- P0116 Engine coolant temperature sensor range or performance
- P0117 Engine coolant temperature sensor circuit low
- P0118 Engine coolant temperature sensor circuit high
- P0119 Engine coolant temperature sensor circuit intermittent
- P0120 Throttle or pedal position sensor A: circuit fault
- P0121 Throttle or pedal position sensor A: out of expected range
- P0122 Throttle or pedal position sensor A: low signal
- P0123 Throttle or pedal position sensor A: high signal
- P0124 Throttle or pedal position sensor A: intermittent signal
- P0125 Engine takes too long to warm up for fuel mixture control
- P0128 Thermostat: coolant not reaching normal operating temperature
- P0130 Oxygen sensor (bank 1, sensor 1): circuit fault
- P0131 Oxygen sensor (bank 1, sensor 1): voltage too low
- P0132 Oxygen sensor (bank 1, sensor 1): voltage too high
- P0133 Oxygen sensor (bank 1, sensor 1): slow response
- P0134 Oxygen sensor (bank 1, sensor 1): no activity
- P0135 Oxygen sensor heater (bank 1, sensor 1): circuit fault
- P0136 Oxygen sensor (bank 1, sensor 2): circuit fault
- P0137 Oxygen sensor (bank 1, sensor 2): voltage too low
- P0138 Oxygen sensor (bank 1, sensor 2): voltage too high
- P0139 Oxygen sensor (bank 1, sensor 2): slow response
- P0140 Oxygen sensor (bank 1, sensor 2): no activity
- P0141 Oxygen sensor heater (bank 1, sensor 2): circuit fault
- P0150 Oxygen sensor (bank 2, sensor 1): circuit fault
- P0151 Oxygen sensor (bank 2, sensor 1): voltage too low
- P0153 Oxygen sensor (bank 2, sensor 1): slow response
- P0155 Oxygen sensor heater (bank 2, sensor 1): circuit fault
- P0156 Oxygen sensor (bank 2, sensor 2): circuit fault
- P0157 Oxygen sensor (bank 2, sensor 2): voltage too low
- P0158 Oxygen sensor (bank 2, sensor 2): voltage too high
- P0160 Oxygen sensor (bank 2, sensor 2): no activity
- P0161 Oxygen sensor heater (bank 2, sensor 2): circuit fault
- P0170 Fuel trim out of limits (bank 1)
- P0171 Mixture too lean (bank 1)
- P0172 System running too rich (bank 1)
- P0173 Fuel trim malfunction (bank 2)
- P0174 System running too lean (bank 2)
- P0175 System running too rich (bank 2)
- P0180 Fuel temperature sensor A circuit malfunction
- P0181 Fuel temperature sensor A range or performance problem
- P0182 Fuel temperature sensor A circuit low
- P0183 Fuel temperature sensor A circuit high
- P0190 Fuel rail pressure sensor circuit malfunction
- P0191 Fuel rail pressure sensor range or performance problem
- P0192 Fuel rail pressure sensor circuit low
- P0193 Fuel rail pressure sensor circuit high
P02xx: Fuel and injectors
- P0200 Injector circuit malfunction
- P0201 Injector circuit malfunction, cylinder 1
- P0202 Injector circuit malfunction, cylinder 2
- P0203 Injector circuit malfunction, cylinder 3
- P0204 Injector circuit malfunction, cylinder 4
- P0205 Injector circuit malfunction, cylinder 5
- P0206 Injector circuit malfunction, cylinder 6
- P0207 Injector circuit malfunction, cylinder 7
- P0208 Injector circuit malfunction, cylinder 8
- P0217 Engine overheating
- P0218 Transmission overheating
- P0219 Engine overspeed condition
- P0220 Throttle or pedal position sensor B circuit malfunction
- P0221 Throttle or pedal position sensor B range or performance problem
- P0222 Throttle or pedal position sensor B circuit low
- P0223 Throttle or pedal position sensor B circuit high
- P0230 Fuel pump primary circuit malfunction
- P0231 Fuel pump secondary circuit low
- P0232 Fuel pump secondary circuit: high signal
- P0234 Turbocharger or supercharger A overboost
- P0235 Turbo boost pressure sensor A: circuit fault
- P0236 Turbo boost pressure sensor A: range or performance problem
- P0237 Turbo boost pressure sensor A: low signal
- P0238 Turbo boost pressure sensor A: high signal
- P0243 Turbo wastegate solenoid A: circuit fault
- P0245 Turbo wastegate solenoid A: low signal
- P0246 Turbo wastegate solenoid A: high signal
- P0261 Cylinder 1 injector: low signal in circuit
- P0262 Cylinder 1 injector: high signal in circuit
- P0264 Cylinder 2 injector: low signal in circuit
- P0265 Cylinder 2 injector: high signal in circuit
- P0267 Cylinder 3 injector: low signal in circuit
- P0268 Cylinder 3 injector: high signal in circuit
- P0270 Cylinder 4 injector: low signal in circuit
- P0271 Cylinder 4 injector: high signal in circuit
- P0299 Turbocharger or supercharger underboost
P03xx: Ignition and misfires
- P0300 Random or multiple cylinder misfire
- P0301 Misfire detected in cylinder 1
- P0302 Misfire detected in cylinder 2
- P0303 Misfire detected in cylinder 3
- P0304 Misfire detected in cylinder 4
- P0305 Misfire detected in cylinder 5
- P0306 Misfire detected in cylinder 6
- P0307 Misfire detected in cylinder 7
- P0308 Misfire detected in cylinder 8
- P0313 Misfire detected with low fuel level
- P0316 Misfire detected on start-up (first 1000 revolutions)
- P0320 Engine speed input (ignition or distributor): circuit fault
- P0321 Ignition or distributor engine speed signal out of range
- P0322 No ignition or distributor engine speed signal
- P0325 Knock sensor 1 circuit fault (bank 1 or single sensor)
- P0326 Knock sensor 1 signal out of range (bank 1 or single sensor)
- P0327 Knock sensor 1 circuit low input (bank 1 or single sensor)
- P0328 Knock sensor 1 circuit high input (bank 1 or single sensor)
- P0330 Knock sensor 2 circuit fault (bank 2)
- P0332 Knock sensor 2 circuit low input (bank 2)
- P0335 Crankshaft position sensor A circuit fault
- P0336 Crankshaft position sensor A signal out of range
- P0337 Crankshaft position sensor A circuit low input
- P0338 Crankshaft position sensor A circuit high input
- P0339 Crankshaft position sensor A circuit intermittent
- P0340 Camshaft position sensor A circuit fault (bank 1)
- P0341 Camshaft position sensor A signal out of range (bank 1)
- P0342 Camshaft position sensor A circuit low input (bank 1)
- P0343 Camshaft position sensor A circuit high input (bank 1)
- P0344 Camshaft position sensor A circuit intermittent (bank 1)
- P0345 Camshaft position sensor A circuit fault (bank 2)
- P0346 Camshaft position sensor A signal out of range (bank 2)
- P0351 Ignition coil A circuit fault
- P0352 Ignition coil B circuit fault
- P0353 Ignition coil C circuit fault
- P0354 Ignition coil D circuit fault
- P0355 Ignition coil E circuit fault
- P0356 Ignition coil F circuit fault
- P0365 Camshaft position sensor B circuit fault (bank 1)
- P0366 Camshaft position sensor B signal out of range (bank 1)
- P0380 Glow plug circuit A fault
- P0381 Glow plug indicator light circuit fault
- P0382 Glow plug circuit B malfunction
P04xx: Emissions control
- P0400 Exhaust gas recirculation (EGR) flow malfunction
- P0401 Exhaust gas recirculation (EGR) flow insufficient
- P0402 Exhaust gas recirculation (EGR) flow excessive
- P0403 EGR control circuit malfunction
- P0404 EGR circuit range or performance problem
- P0405 EGR sensor A circuit low
- P0406 EGR sensor A circuit high
- P0407 EGR sensor B circuit low
- P0408 EGR sensor B circuit high
- P0409 EGR sensor A circuit malfunction
- P0410 Secondary air injection system malfunction
- P0411 Secondary air injection incorrect flow detected
- P0412 Secondary air switching valve A circuit malfunction
- P0418 Secondary air injection relay A circuit malfunction
- P0420 Catalytic converter efficiency below threshold (bank 1)
- P0421 Warm up catalyst efficiency below threshold (bank 1)
- P0430 Catalytic converter efficiency below threshold (bank 2)
- P0431 Warm up catalyst efficiency below threshold (bank 2)
- P0440 Evaporative emission (EVAP) system malfunction
- P0441 EVAP system incorrect purge flow
- P0442 EVAP system small leak detected
- P0443 EVAP purge control valve circuit malfunction
- P0444 EVAP purge control valve circuit open
- P0445 EVAP purge control valve circuit shorted
- P0446 EVAP vent control circuit malfunction
- P0449 EVAP vent valve or solenoid circuit malfunction
- P0451 EVAP pressure sensor range or performance problem
- P0452 EVAP pressure sensor circuit low
- P0453 EVAP pressure sensor circuit high
- P0454 EVAP system pressure sensor intermittent signal
- P0455 EVAP system large leak detected
- P0456 EVAP system very small leak detected
- P0457 EVAP system leak: fuel cap loose or missing
- P0458 EVAP purge control valve circuit low
- P0459 EVAP purge control valve circuit high
- P0460 Fuel level sensor circuit malfunction
- P0461 Fuel level sensor circuit range/performance
- P0462 Fuel level sensor circuit low input
- P0463 Fuel level sensor circuit high input
- P0480 Cooling fan 1 control circuit malfunction
- P0481 Cooling fan 2 control circuit malfunction
- P0491 Secondary air injection system insufficient flow (bank 1)
- P0492 Secondary air injection system insufficient flow (bank 2)
- P0496 EVAP system high purge flow
- P0497 EVAP system low purge flow
P05xx: Speed, idle and auxiliary inputs
- P0500 Vehicle speed sensor malfunction
- P0501 Vehicle speed sensor range/performance
- P0502 Vehicle speed sensor circuit low input
- P0503 Vehicle speed sensor intermittent, erratic or high
- P0504 Brake switch A/B correlation
- P0505 Idle control system malfunction
- P0506 Idle speed lower than expected
- P0507 Idle speed higher than expected
- P0513 Incorrect immobiliser key
- P0520 Oil pressure sensor/switch circuit malfunction
- P0521 Oil pressure sensor/switch range/performance
- P0522 Oil pressure sensor/switch low voltage
- P0523 Oil pressure sensor/switch high voltage
- P0524 Engine oil pressure too low
- P0530 A/C refrigerant pressure sensor: circuit fault
- P0532 A/C refrigerant pressure sensor: low input
- P0533 A/C refrigerant pressure sensor: high input
- P0560 System voltage: malfunction
- P0562 System voltage low
- P0563 System voltage high
- P0571 Cruise control brake switch A: circuit fault
P06xx: Control unit and auxiliary outputs
- P0600 Serial communication link fault
- P0601 Internal control module memory checksum error
- P0602 Control module programming error
- P0603 Internal control module keep alive memory (KAM) error
- P0604 Internal control module random access memory (RAM) error
- P0605 Internal control module read only memory (ROM) error
- P0606 ECM/PCM processor fault
- P0607 Control module performance
- P0615 Starter relay: circuit fault
- P0616 Starter relay: circuit low
- P0617 Starter relay: circuit high
- P0620 Generator control: circuit fault
- P0621 Generator lamp L control: circuit fault
- P0622 Generator field F control: circuit fault
- P0627 Fuel pump A control: circuit open or faulty
- P0638 Throttle actuator control: range or performance (bank 1)
- P0641 Sensor reference voltage A: circuit open or faulty
- P0642 Sensor reference voltage A: circuit low
- P0643 Sensor reference voltage A: circuit high
- P0645 A/C clutch relay control: circuit fault
- P0650 Malfunction indicator lamp (MIL) control: circuit fault
- P0651 Sensor reference voltage B: circuit open or faulty
- P0652 Sensor reference voltage B: circuit low
- P0653 Sensor reference voltage B: circuit high
- P0670 Glow plug module control: circuit fault
- P0671 Cylinder 1 glow plug: circuit fault
- P0672 Cylinder 2 glow plug: circuit fault
- P0673 Cylinder 3 glow plug: circuit fault
- P0674 Cylinder 4 glow plug: circuit fault
- P0685 ECM/PCM power relay control: circuit open
- P0686 ECM/PCM power relay control: circuit low
- P0687 ECM/PCM power relay control: circuit high
- P0688 ECM/PCM power relay sense: circuit open
- P0691 Fan 1 control: circuit low
- P0692 Fan 1 control: circuit high
P07xx: Transmission
- P0700 Transmission control system: fault detected
- P0701 Transmission control system: range/performance
- P0702 Transmission control system: electrical fault
- P0703 Torque converter/brake switch B: circuit fault
- P0705 Transmission range sensor: circuit fault
- P0706 Transmission range sensor: range/performance
- P0710 Transmission fluid temperature sensor: circuit fault
- P0711 Transmission fluid temperature sensor: range/performance
- P0712 Transmission fluid temperature sensor: circuit low
- P0713 Transmission fluid temperature sensor: circuit high
- P0714 Transmission fluid temperature sensor: circuit intermittent
- P0715 Input/turbine speed sensor: circuit fault
- P0716 Input/turbine speed sensor: range/performance
- P0717 Input/turbine speed sensor: no signal
- P0720 Output speed sensor: circuit fault
- P0721 Output speed sensor: range/performance
- P0722 Output speed sensor: no signal
- P0725 Engine speed input to gearbox: circuit fault
- P0729 Incorrect gear ratio in sixth gear
- P0730 Incorrect gear ratio in the automatic gearbox
- P0731 Incorrect gear ratio in first gear
- P0732 Incorrect gear ratio in second gear
- P0733 Incorrect gear ratio in third gear
- P0734 Incorrect gear ratio in fourth gear
- P0735 Incorrect gear ratio in fifth gear
- P0740 Torque converter clutch circuit fault
- P0741 Torque converter clutch poor performance or not engaging
- P0742 Torque converter clutch stuck engaged
- P0743 Torque converter clutch circuit electrical fault
- P0744 Torque converter clutch circuit intermittent fault
- P0745 Gearbox pressure control solenoid fault
- P0746 Pressure control solenoid poor performance or stuck off
- P0747 Pressure control solenoid stuck on
- P0748 Pressure control solenoid electrical fault
- P0750 Shift solenoid A fault
- P0751 Shift solenoid A poor performance or stuck off
- P0752 Shift solenoid A stuck on
- P0753 Shift solenoid A electrical fault
- P0755 Shift solenoid B fault
- P0756 Shift solenoid B poor performance or stuck off
- P0757 Shift solenoid B stuck on
- P0758 Shift solenoid B electrical fault
- P0760 Shift solenoid C fault
- P0761 Shift solenoid C poor performance or stuck off
- P0762 Shift solenoid C stuck on
- P0763 Shift solenoid C electrical fault
- P0765 Shift solenoid D fault
- P0770 Shift solenoid E fault
- P0771 Shift solenoid E: performance problem or stuck off
- P0776 Pressure control solenoid B: performance problem or stuck off
- P0777 Pressure control solenoid B stuck on
- P0780 Automatic gearbox shift malfunction
- P0781 Automatic gearbox 1-2 shift malfunction
- P0782 Automatic gearbox 2-3 shift malfunction
- P0783 Automatic gearbox 3-4 shift malfunction
P08xx: Transmission
- P0841 Transmission fluid pressure sensor/switch A: circuit range or performance
- P0842 Transmission fluid pressure sensor/switch A: circuit low
- P0843 Transmission fluid pressure sensor/switch A: circuit high
- P0868 Transmission fluid pressure low
P0Axx: Hybrid and electric
- P0A0F Engine failed to start
- P0A1F Battery energy control module fault
- P0A7F Hybrid battery pack deterioration
- P0A80 Replace hybrid battery pack
- P0A94 DC/DC converter performance
- P0AA6 Hybrid high-voltage system isolation fault
P20xx: Emissions: catalysts and AdBlue
- P2002 Diesel particulate filter efficiency below threshold (bank 1)
- P2003 Diesel particulate filter efficiency below threshold (bank 2)
- P2004 Intake manifold runner control stuck open (bank 1)
- P2005 Intake manifold runner control stuck open (bank 2)
- P2006 Intake manifold runner control stuck closed (bank 1)
- P2007 Intake manifold runner control stuck closed (bank 2)
- P2008 Intake manifold runner control circuit open or faulty (bank 1)
- P2009 Intake manifold runner control circuit low (bank 1)
- P2015 Intake runner position sensor: range or performance problem (bank 1)
- P2016 Intake manifold runner position sensor circuit low (bank 1)
- P2017 Intake manifold runner position sensor circuit high (bank 1)
- P2031 Exhaust gas temperature sensor circuit fault (bank 1, sensor 2)
- P2032 Exhaust gas temperature sensor circuit low (bank 1, sensor 2)
- P2033 Exhaust gas temperature sensor circuit high (bank 1, sensor 2)
- P2047 AdBlue injector circuit open or faulty (bank 1, unit 1)
- P204F Reductant (AdBlue) system performance (bank 1)
- P207F Reductant (AdBlue) quality performance
- P2080 Exhaust gas temperature sensor reading out of range (bank 1, sensor 1)
- P2081 Exhaust gas temperature sensor circuit intermittent (bank 1, sensor 1)
- P2084 Exhaust gas temperature sensor reading out of range (bank 1, sensor 2)
- P2088 Camshaft position actuator A control circuit low (bank 1)
- P2089 Camshaft actuator A control circuit high (bank 1)
- P2090 Camshaft actuator B control circuit low (bank 1)
- P2091 Camshaft actuator B control circuit high (bank 1)
- P2096 Post-catalyst fuel trim system too lean (bank 1)
- P2097 Post-catalyst fuel trim system too rich (bank 1)
- P2098 Post-catalyst fuel trim system too lean (bank 2)
- P2099 Post-catalyst fuel trim system too rich (bank 2)
- P20B9 Reductant (AdBlue) heater A control circuit open or faulty
- P20E8 Reductant (AdBlue) pressure too low
- P20EE SCR NOx catalyst efficiency below threshold (bank 1)
P21xx: Throttle, injection and emissions
- P2100 Throttle actuator A control motor circuit open
- P2101 Throttle actuator A control motor circuit range or performance
- P2102 Throttle actuator A control motor circuit low
- P2104 Throttle control system: forced idle
- P2105 Throttle control system: forced engine shutdown
- P2106 Throttle control system: forced limited power
- P2107 Throttle actuator control module processor fault
- P2108 Throttle actuator control module performance
- P2110 Throttle control system: forced limited RPM
- P2111 Throttle control system stuck open
- P2112 Throttle control system stuck closed
- P2118 Throttle actuator control motor current range or performance
- P2119 Throttle actuator control throttle body range or performance
- P2120 Throttle or pedal position sensor D circuit fault
- P2122 Throttle or pedal position sensor D circuit low
- P2123 Throttle or pedal position sensor D circuit high
- P2125 Throttle or pedal position sensor E circuit fault
- P2127 Throttle or pedal position sensor E circuit low
- P2128 Throttle or pedal position sensor E circuit high
- P2135 Throttle or pedal position sensors A and B voltage mismatch
- P2138 Throttle or pedal position sensors D and E voltage mismatch
- P2146 Fuel injector group A supply voltage circuit or open
- P2177 System too lean off idle (bank 1)
- P2178 Mixture too rich away from idle (bank 1)
- P2179 Mixture too lean away from idle (bank 2)
- P2187 Mixture too lean at idle (bank 1)
- P2188 Mixture too rich at idle (bank 1)
- P2189 Mixture too lean at idle (bank 2)
- P2191 Mixture too lean at higher load (bank 1)
- P2195 Oxygen sensor signal biased or stuck lean (bank 1, sensor 1)
- P2196 Oxygen sensor signal biased or stuck rich (bank 1, sensor 1)
- P2197 Oxygen sensor signal biased or stuck lean (bank 2, sensor 1)
- P2198 Oxygen sensor signal biased or stuck rich (bank 2, sensor 1)
P22xx: NOx sensors, oxygen sensors and emissions
- P2200 NOx sensor circuit fault (bank 1)
- P2201 NOx sensor circuit range or performance problem (bank 1)
- P2227 Barometric pressure sensor A range or performance problem
- P2228 Barometric pressure sensor A circuit low
- P2229 Barometric pressure sensor A circuit high
- P2237 Oxygen sensor current control circuit open (bank 1, sensor 1)
- P2243 Oxygen sensor reference voltage circuit open (bank 1, sensor 1)
- P2263 Turbocharger or supercharger boost system performance
- P2264 Water in fuel sensor circuit fault
- P2269 Water in fuel detected
- P2270 Oxygen sensor signal biased or stuck lean (bank 1, sensor 2)
- P2271 Oxygen sensor signal biased or stuck rich (bank 1, sensor 2)
- P2272 Oxygen sensor signal biased or stuck lean (bank 2, sensor 2)
- P2273 Oxygen sensor signal biased or stuck rich (bank 2, sensor 2)
- P2279 Intake air system leak
- P2293 Fuel pressure regulator 2 performance
- P2299 Brake pedal and accelerator pedal positions incompatible
P23xx: Ignition coils and engine
- P2300 Ignition coil A primary control circuit low
- P2301 Ignition coil A primary control circuit high
- P2303 Ignition coil B primary control circuit low
- P2304 Ignition coil B primary control circuit high
- P2306 Ignition coil C primary control circuit low
- P2307 Ignition coil C primary control circuit high
P24xx: EGR, EVAP and particulate filter
- P2400 EVAP leak detection pump control circuit open or faulty
- P2413 Exhaust gas recirculation (EGR) system performance
- P2414 O2 sensor exhaust sample error (bank 1, sensor 1)
- P2425 EGR cooler valve control circuit open or faulty
- P242F Diesel particulate filter restriction: ash accumulation
- P244A Diesel particulate filter differential pressure too low (bank 1)
- P244B Diesel particulate filter differential pressure too high (bank 1)
- P2452 Diesel particulate filter pressure sensor A circuit
- P2453 Diesel particulate filter pressure sensor A range/performance
- P2454 Diesel particulate filter pressure sensor A circuit low
- P2455 Diesel particulate filter pressure sensor A circuit high
- P2458 Diesel particulate filter regeneration duration
- P2459 Diesel particulate filter regeneration frequency
- P2463 Diesel particulate filter restriction: soot accumulation
P25xx: Auxiliary inputs and electrical system
P2Axx: Engine and emissions
P2Bxx: Engine and emissions
U00xx: Communication buses
U01xx: Lost communication with control units
- U0100 Lost communication with engine control module (ECM/PCM A)
- U0101 Lost communication with transmission control module (TCM)
- U0102 Lost communication with transfer case control module
- U0103 Lost communication with the gear shift module
- U0104 Lost communication with the cruise control module
- U0107 Lost communication with the throttle actuator control module
- U0121 Lost communication with the ABS control module
- U0126 Lost communication with the steering angle sensor module
- U0128 Lost communication with the park brake control module
- U0131 Lost communication with the power steering control module
- U0140 Lost communication with the body control module (BCM)
- U0141 Lost communication with body control module A
- U0146 Lost communication with gateway A
- U0151 Lost communication with the restraints control module
- U0155 Lost communication with the instrument cluster
- U0164 Lost communication with the HVAC control module
- U0168 Lost communication with the vehicle security module (immobiliser)
- U0184 Lost communication with the radio
- U0198 Lost communication with the telematics control module
U04xx: Invalid data between control units
- U0401 Invalid data received from the engine control module (ECM/PCM)
- U0402 Invalid data received from the transmission control module
- U0415 Invalid data received from the ABS control module
- U0416 Invalid data received from the vehicle dynamics control module
- U0422 Invalid data received from the body control module
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Steady or flashing, whether you can keep going and why it sometimes goes off by itself.
The Spanish ITV and the OBD socket: what they read
What the Spanish test centre reads through the OBD socket, what counts as major and how to avoid surprises.
The OBD2 readiness monitors
What each monitor checks, why they show not ready and how they complete.
What OBD2 is and since when your car has it
What it’s for, the difference between OBD2 and EOBD, and the year it became mandatory.
The OBD2 connector: where it is and what each pin carries
Where to look for it and what each of its 16 pins is for.
The OBD2 protocols: how your car talks
CAN, K-line (ISO 9141-2 and KWP2000) and J1850: which car uses which.
The OBD2 modes, one by one
Live data, fault codes, clearing, pending, VIN and permanent: what each mode asks for.
OBD2 live data and its normal values
Rpm, temperatures, fuel trims, oxygen sensors, load and boost: what each PID is and which value is normal.
Coming soon
Mid to late October 2026
If you want to try it in your car before anyone else, send us your email and we will add you as a tester.
info@finalobd.com