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
P0174
Powertrain
The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction…
Moderate
P0420
Powertrain
The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly.
Low
P0101
Powertrain
The MAF sensor's airflow reading doesn't match what the engine computer expects…
Low
P0113
Powertrain
The intake air temperature signal is stuck at maximum voltage, which usually means an open…
Low
P0135
Powertrain
The heater inside the upstream oxygen sensor on bank 1 isn't working or its circuit is faulty.
Low
P0171
Powertrain
The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees…
Moderate
All codes (539)
P0057
Powertrain
The heater behind the bank 2 converter draws no current – open element or cut, torn…
Minor
P0068
Powertrain
The airflow the engine measures doesn't match what the throttle opening says it should be.
Moderate
P0069
Powertrain
With the engine stopped, the manifold pressure and barometric pressure readings don't agree.
Low
P0075
Powertrain
The intake cam timing solenoid on bank 1 has an open, short or bad driver circuit, so cam…
Low
P0081
Powertrain
Electrical fault in the bank 2 intake cam solenoid on a V6 or V8; only one cylinder bank loses…
Low
P0087
Powertrain
Measured fuel pressure has dropped well below what the engine computer is asking for.
High
P0088
Powertrain
Rail pressure is running well above the value the engine computer is commanding.
Moderate
P0089
Powertrain
The fuel pressure regulator is getting its commands but pressure isn't responding the way it…
Moderate
P0090
Powertrain
The engine computer sees an electrical fault in the wiring or coil of the fuel pressure control…
Moderate
P0093
Powertrain
Rail pressure is dropping faster than injection explains: fuel may be escaping. Stop and check…
Critical
P0100
Powertrain
The PCM sees an electrical fault in the MAF sensor circuit: signal missing, erratic or not…
Low
P0101
Powertrain
The MAF sensor's airflow reading doesn't match what the engine computer expects…
Low
P0102
Powertrain
The MAF signal is too weak for the PCM to accept, so it treats the circuit as dead…
Moderate
P0103
Powertrain
The MAF claims more airflow than the engine could possibly take in, usually from a short…
Low
P0105
Powertrain
The PCM lost a usable signal from the manifold pressure sensor: dropouts, noise or values it…
Moderate
P0106
Powertrain
The MAP sensor works electrically, but its pressure reading doesn't fit what the engine…
Low
P0107
Powertrain
The MAP signal has fallen to almost zero volts, usually from a lost 5-volt reference or an open…
Moderate
P0108
Powertrain
The MAP signal is pinned near 5 volts, so the PCM sees impossibly high manifold pressure even…
Moderate
P0110
Powertrain
The PCM can't get a stable, believable signal from the intake air temperature sensor circuit.
Low
P0111
Powertrain
The IAT reading is electrically fine but doesn't match the other temperatures the ECU knows.
Minor
P0112
Powertrain
The IAT signal is near zero volts, so the PCM believes the intake air is scorching hot, usually…
Low
P0113
Powertrain
The intake air temperature signal is stuck at maximum voltage, which usually means an open…
Low
P0114
Powertrain
The IAT signal keeps dropping out or jumping for a moment and coming back, a sign of a loose…
Minor
P0115
Powertrain
The ECU can't get a usable coolant temperature signal; the sensor circuit is open, shorted…
Low
P0116
Powertrain
The coolant temperature signal is electrically fine but doesn't behave the way the PCM expects.
Low
P0117
Powertrain
The coolant temperature signal is pinned near zero volts, which the PCM reads as an impossibly…
Low
P0118
Powertrain
The coolant sensor signal sits near 5 volts, so the PCM thinks the engine is frozen solid…
Low
P0120
Powertrain
The throttle position signal dropped out or glitched, so the PCM no longer trusts the throttle…
Moderate
P0121
Powertrain
The throttle position reading is electrically valid but doesn't agree with engine load, airflow…
Moderate
P0122
Powertrain
The throttle position signal fell to nearly 0 volts, lower than a closed throttle could ever…
Moderate