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)
P0A94
Powertrain
A hybrid voltage converter isn't delivering the voltage it should – on Toyotas, the boost…
High
P0A95
Powertrain
The main fuse in the high-voltage battery circuit has opened or its circuit reads open…
Critical
P0AA6
Powertrain
High voltage is leaking toward the car body somewhere – an insulation fault that must be found…
High
P0AFA
Powertrain
Total high-voltage battery voltage dropped below the minimum the system allows, so power…
High
P1000
Ford · Powertrain
Ford's computer hasn't finished all its self-tests yet. It's a status message, not a fault.
Minor
P1101
Chevrolet · Powertrain
GM's engine computer found that measured airflow doesn't agree with what it expects.
Low
P1128
Jeep · Powertrain
Your Jeep's PCM never switched bank 1 from preset fueling to O2-sensor feedback after…
Low
P1128
Volkswagen · Powertrain
VW's part-load fuel adaptation has maxed out adding fuel on bank 1 – the engine runs lean as…
Moderate
P1129
Jeep · Powertrain
The PCM couldn't switch bank 2 of your Jeep's V6 or V8 into oxygen-sensor-controlled fueling…
Low
P1131
Ford · Powertrain
Ford's front O2 sensor on bank 1 stays lean even after the PCM has added all the fuel it…
Low
P1132
Ford · Powertrain
Ford's front O2 sensor on bank 1 keeps reading rich even though the PCM has pulled out as much…
Low
P1133
Chevrolet · Powertrain
The front oxygen sensor on bank 1 isn't flipping between rich and lean often enough during GM's…
Low
P1134
Chevrolet · Powertrain
Bank 1's front O2 sensor reacts much faster in one direction (rich or lean) than the other.
Low
P1135
Toyota · Powertrain
The heater inside Toyota's upstream air/fuel ratio sensor is drawing too much or too little…
Low
P1136
Volkswagen · Powertrain
At idle the VW computer is adding the maximum fixed amount of fuel on bank 1 – a classic vacuum…
Low
P1137
Volkswagen · Powertrain
At idle the VW computer is pulling out as much fuel as it's allowed on bank 1 and the mix…
Low
P1151
Ford · Powertrain
On a Ford V6 or V8, the front O2 sensor on the bank 2 side stays lean and never switches back…
Low
P1152
Ford · Powertrain
On a Ford V6 or V8, the bank 2 front O2 sensor sticks on rich even after the PCM leaned that…
Low
P1153
Chevrolet · Powertrain
The front O2 sensor on the passenger-side bank of a Chevy V6/V8 isn't cycling rich-lean often…
Low
P1154
Chevrolet · Powertrain
On a Chevy V6/V8, the bank 2 front O2 sensor rises and falls at clearly different speeds.
Low
P1155
Toyota · Powertrain
The heater in the front-bank air/fuel ratio sensor of a Toyota V6 or V8 is out of its current…
Low
P1157
Honda · Powertrain
The signal lines of Honda's upstream air/fuel ratio sensor read too high, usually an open…
Low
P1166
Honda · Powertrain
The circuit that powers the heater in Honda's upstream A/F sensor is open, shorted or unpowered.
Low
P1167
Honda · Powertrain
The upstream A/F sensor heater is powered but isn't drawing the current or heating the sensor…
Low
P1217
Nissan · Powertrain
Nissan's ECM saw engine coolant get hotter than it should, usually because the radiator fan…
Critical
P1233
Ford · Powertrain
The Ford PCM lost the status signal from the fuel pump driver module, so fuel pump control…
Moderate
P1259
Honda · Powertrain
The PCM saw the VTEC solenoid or VTEC oil pressure switch misbehave on an older Honda VTEC…
Moderate
P1260
Ford · Powertrain
Ford's Passive Anti-Theft System didn't accept the key, so the PCM shut off fuel and the engine…
Moderate
P1272
Nissan · Powertrain
The front air/fuel ratio sensor on bank 1 isn't sending a usable, moving signal to the Nissan…
Moderate
P1273
Nissan · Powertrain
Nissan's ECM sees the front air/fuel ratio sensor on bank 1 reading lean for too long and flags…
Low