Powertrain Codes (P-Codes): Full List
Powertrain codes start with P and cover the engine, fuel and ignition systems, emission controls and the transmission. They are the codes that most often turn on the check engine light and the ones most relevant to a smog check or emissions test. The third character narrows it down: 1–2 fuel and air metering, 3 ignition and misfire, 4 emission controls, 5 speed and idle, 6 computer and outputs, 7–9 transmission, A hybrid.
539Codes
2.7Average severity
12%High or critical
20%DIY-friendly
Severity distribution
Most viewed
P0135
Powertrain
The heater inside the upstream oxygen sensor on bank 1 isn't working or its circuit is faulty.
Low
P0174
Powertrain
The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction…
Moderate
P0113
Powertrain
The intake air temperature signal is stuck at maximum voltage, which usually means an open…
Low
P0171
Powertrain
The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees…
Moderate
P0172
Powertrain
The engine computer is pulling as much fuel as it's allowed on bank 1 and the mixture is still…
Moderate
P0299
Powertrain
The turbo or supercharger isn't building the boost pressure the engine computer is asking for.
Moderate
All codes (318)
P175D
Volkswagen · Powertrain
The DSG computer saw clutch 1 let go while it was supposed to stay engaged, so it cut…
High
P1778
Nissan · Powertrain
The Jatco CVT's step motor is being commanded, but the pulley ratio isn't following it as it…
High
P17F0
Nissan · Powertrain
The TCM detected judder it blames on the CVT itself, usually belt or pulley slip inside…
High
P17F1
Nissan · Powertrain
The TCM caught a judder event it links to the CVT's control valve (valve body), not yet to belt…
Moderate
P1E00
Chevrolet · Powertrain
Volt/Bolt pointer code: the hybrid/EV controller found a fault and asked for the check engine…
Moderate
P2002
Powertrain
The ECU thinks the diesel particulate filter isn't trapping soot properly — or it can't measure…
Moderate
P2006
Powertrain
The intake swirl or runner flaps stay shut when the ECU wants them open, choking airflow…
Moderate
P204F
Powertrain
The DEF/SCR system isn't cutting NOx the way it should; ignored, it leads to a severe speed…
Moderate
P207F
Powertrain
The ECM thinks the DEF in the tank is too weak or contaminated, often right after a refill.
Moderate
P20E8
Powertrain
The DEF pump can't build or hold enough pressure; suspect a leak, frozen line, clogged filter…
Moderate
P20EE
Powertrain
The SCR catalyst isn't removing enough NOx; DEF quality, dosing, a NOx sensor or the catalyst…
Moderate
P2100
Powertrain
The computer can't push current through the throttle motor – the circuit to the throttle body…
High
P2101
Powertrain
The throttle plate isn't reaching the position the computer asks for, fast enough or accurately…
Moderate
P2102
Powertrain
Too little current or voltage reaches the throttle motor – usually resistance in the feed, not…
Moderate
P2103
Powertrain
The throttle motor circuit draws too much current – a short, a shorted motor or a plate that…
Moderate
P2104
Powertrain
A fail-safe has locked the engine at idle and the gas pedal no longer works – another code…
High
P2105
Powertrain
The engine computer shut the engine off on purpose because it could no longer control…
Critical
P2106
Powertrain
Reduced-power limp mode: the PCM caught a throttle or pedal fault – look for the companion code.
Moderate
P2107
Powertrain
The processor supervising the electronic throttle failed its self-check – a computer fault, not…
High
P2108
Powertrain
The throttle control module isn't performing as expected – check its power, data link…
Moderate
P2110
Powertrain
The PCM is capping engine speed with fuel cut-off because it can't fully trust or close…
Moderate
P2111
Powertrain
The throttle plate stayed more open than commanded – a real safety concern until you know why.
High
P2112
Powertrain
The PCM asked the throttle to open, but it stayed shut – the engine can't get air, so it bogs…
High
P2118
Powertrain
The throttle motor is drawing more or less current than the PCM expects to hold the plate where…
Moderate
P2119
Powertrain
The throttle plate isn't reaching the position the PCM commands, or won't spring back to its…
Moderate
P2120
Powertrain
The PCM lost a usable signal from the main gas pedal sensor, often only for a moment.
Moderate
P2121
Powertrain
The main gas pedal signal stays within normal voltage but moves in a way a real pedal can't.
Moderate
P2122
Powertrain
The main gas pedal sensor reads close to 0 volts, below anything a working pedal produces…
Moderate
P2123
Powertrain
The main gas pedal sensor reads near its full 5-volt supply or higher, even with your foot off…
Moderate
P2125
Powertrain
The PCM lost a valid signal from the second, cross-check sensor in the gas pedal.
Moderate