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)
P0670
Powertrain
The engine computer can't properly control or hear back from the diesel's glow plug control…
Low
P0671
Powertrain
The glow plug in cylinder 1 or its wire isn't drawing normal current. Usually the plug itself…
Low
P0685
Powertrain
The engine computer can't switch its own main power relay – open coil, blown fuse or broken…
High
P0686
Powertrain
The main relay control line is being pulled to ground – usually a shorted relay coil…
Moderate
P0687
Powertrain
The main relay control line sits at battery voltage – the relay may never switch on or never…
Moderate
P0690
Powertrain
The ECM still sees power coming through its main relay when the relay should be off – often…
Low
P069E
Chevrolet · Powertrain
The fuel pump control module stored its own fault and asked the engine computer for the check…
Moderate
P06DD
Powertrain
The ECM commanded an oil pressure change and the measured pressure didn't respond – check…
High
P0700
Powertrain
The transmission computer found a fault and asked for the check engine light – read the TCM…
Moderate
P0705
Powertrain
The computer can't make sense of the gear selector position signal – P, R, N, D may be misread.
Moderate
P0706
Powertrain
The range sensor works electrically, but its reading doesn't match where the lever and gears…
Moderate
P0707
Powertrain
The range sensor signal voltage is below its lowest valid value – usually a short to ground…
Moderate
P0710
Powertrain
The transmission computer lost a usable fluid temperature signal and is guessing…
Low
P0711
Powertrain
The fluid temperature reading doesn't behave like real fluid – it warms too slowly, too fast…
Moderate
P0712
Powertrain
The fluid temperature signal voltage is too low, so the computer thinks the fluid is extremely…
Moderate
P0715
Powertrain
The transmission computer has lost a reliable input-shaft speed signal, so shifts get harsh…
Moderate
P0716
Powertrain
The input speed signal is there but erratic or illogical – dropouts, spikes or values that…
Moderate
P0717
Powertrain
The input speed sensor reports zero while the engine runs and the car moves – the signal…
Moderate
P0720
Powertrain
Electrical fault in the output shaft speed signal – shift timing and sometimes the speedometer…
Moderate
P0721
Powertrain
The output speed signal is noisy, drops out or doesn't agree with wheel speed or input speed.
Low
P0722
Powertrain
The output speed sensor sends nothing while the car moves – shifting and often the speedometer…
Moderate
P0730
Powertrain
The transmission computer sees input and output shaft speeds that don't fit the gear it…
High
P0731
Powertrain
While in first gear, the transmission's input and output speeds don't match the first-gear…
Moderate
P0732
Powertrain
Second gear isn't holding: the input-to-output speed ratio in 2nd is outside the expected range.
Moderate
P0733
Powertrain
Third gear slips: input shaft speed doesn't match output speed times the 3rd-gear ratio.
Moderate
P0734
Powertrain
Fourth gear (overdrive on four-speed units) doesn't hold the expected input-to-output speed…
Moderate
P0735
Powertrain
Fifth gear slips or isn't fully applied; the TCM measures a ratio that doesn't fit 5th.
Moderate
P0740
Powertrain
The computer found an open or faulty circuit to the torque converter clutch solenoid, so lockup…
Low
P0741
Powertrain
The torque converter lockup clutch slips or won't engage when the computer commands it.
Moderate
P0742
Powertrain
The converter lockup clutch stays applied when it should be released, which can stall…
High