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)
P0743
Powertrain
The TCC solenoid circuit shows an electrical fault such as a short, overcurrent or out-of-range…
Low
P0744
Powertrain
Lockup control drops in and out: an intermittent TCC circuit, or on some makes a lockup…
Moderate
P0746
Powertrain
Solenoid A doesn't control pressure as commanded: harsh or soft shifts, or limp mode.
Moderate
P0748
Powertrain
The TCM detected an electrical fault (open, short or wrong current) in pressure control…
Moderate
P0750
Powertrain
The transmission computer sees a fault in shift solenoid A or its circuit and can't use it…
Moderate
P0751
Powertrain
Solenoid A is wired fine but its valve isn't doing its job, so gears are missing – often stuck…
High
P0753
Powertrain
The control circuit for shift solenoid A reads open, shorted or out of range – an electrical…
Moderate
P0755
Powertrain
The TCM detects an electrical problem with shift solenoid B, the second on/off shift valve.
Moderate
P0756
Powertrain
Solenoid B isn't moving fluid the way the TCM expects – the car may pull away in 3rd or 4th.
High
P0760
Powertrain
A fault in shift solenoid C's circuit – usually means lost overdrive or upper gears, or limp…
Moderate
P0770
Powertrain
Solenoid E in a five- or six-speed automatic isn't working as commanded: electrical fault…
Moderate
P0773
Powertrain
The transmission computer found an open, short or wrong current in the solenoid E circuit…
Moderate
P0776
Powertrain
Pressure control solenoid B isn't delivering the pressure the TCM asks for – harsh or slipping…
Moderate
P0780
Powertrain
A gear change didn't complete the way the TCM expected, but it can't pin the fault to one part.
Moderate
P0781
Powertrain
The upshift from 1st to 2nd is too slow, slips or never completes properly.
Moderate
P07A3
Ford · Powertrain
The PowerShift's odd-gear clutch isn't letting go when the TCM commands it open, so the car…
High
P0841
Powertrain
Pressure sensor or switch A reports a value that doesn't fit the gear or pressure the TCM…
Moderate
P0851
Powertrain
The engine computer sees the park/neutral input stuck at low voltage, often from a short…
Low
P0852
Powertrain
The park/neutral input reads too high, usually from an open circuit, unplugged connector or bad…
Low
P0868
Powertrain
Measured transmission line pressure is below what the TCM commanded – clutches can slip…
High
P0884
Powertrain
The transmission computer's power supply dropped out briefly – usually a battery, ground…
Moderate
P0887
Powertrain
The circuit that switches the transmission power relay reads high voltage when it shouldn't.
Moderate
P0894
Powertrain
The transmission computer measured slip inside the gearbox that shouldn't be there. Clutches…
High
P090C
Ford · Powertrain
The PowerShift TCM sees a low signal on the motor that works clutch B, the even-gear…
Moderate
P0A0F
Powertrain
The hybrid system spun the gas engine with its motor-generator to start it, but the engine…
High
P0A1F
Powertrain
The module that manages the high-voltage battery failed its self-check or reports implausible…
Moderate
P0A7E
Powertrain
The high-voltage battery got too hot. A clogged cooling intake or dirty fan is the usual cause.
Moderate
P0A7F
Powertrain
The battery computer has calculated that the whole high-voltage pack has worn past its usable…
Moderate
P0A80
Powertrain
The hybrid system sees weak or unbalanced modules in the high-voltage battery and flags…
Moderate
P0A93
Powertrain
The inverter's separate coolant loop isn't carrying heat away – usually a dead electric…
High