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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 distributionSeverity distribution

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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 P0300 Powertrain The engine computer sees misfires that jump between cylinders or hit several cylinders at once. High P0420 Powertrain The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. Low P0430 Powertrain The bank 2 converter on a V6, V8 or split-exhaust engine isn't cleaning the exhaust well enough. Low P0101 Powertrain The MAF sensor's airflow reading doesn't match what the engine computer expects… Low

All codes (318)

All Severity 3+ Severity 4+
P2458 Powertrain A DPF regen took too long or never finished, usually from short trips or exhaust that won't get… Moderate P2459 Powertrain The DPF is regenerating far more often than it should for the miles driven. Moderate P2463 Powertrain The DPF is loaded with more soot than the ECU allows; it needs a regen or cleaning before it… High P246C Powertrain The DPF is so restricted that the ECM has cut engine power to protect the turbo, EGR system… High P2502 Powertrain The ECM distrusts the charging system – no output, wrong voltage or an implausible alternator… Moderate P2503 Powertrain The alternator can't reach the voltage the ECM asks for – usually a worn alternator or slipping… Moderate P2504 Powertrain The charging system is overcharging – too much voltage can boil the battery and damage… High P25A2 Chevrolet · Powertrain The brake module stored a fault and asked the engine computer to turn on the check engine light. Moderate P2647 Powertrain The VTEC oil pressure switch reports the high-lift rockers engaged while the engine computer… Moderate P26B7 Ford · Powertrain The PCM sees an open circuit to the electric coolant bypass valve on Ford's 1.6L EcoBoost… Moderate P2714 Powertrain Transmission pressure solenoid D isn't regulating pressure as commanded – a classic source… Moderate P2716 Powertrain The transmission computer sees an open or short in the circuit of pressure control solenoid D. Moderate P2BAC Powertrain EGR has been shut off because of a fault, so NOx is above the limit; fix the EGR code stored… Moderate P3000 Toyota · Powertrain Toyota's hybrid computer flags a fault in the high-voltage battery system and limits hybrid… High P3190 Toyota · Powertrain The hybrid computer asked the gas engine for power and got less than expected. Moderate P3191 Toyota · Powertrain The hybrid system spun the gas engine with its motor-generator, but the engine never fired up. High P3400 Powertrain Cylinder shut-off on bank 1 (AFM, DFM, MDS or VCM) isn't doing what the engine computer… Moderate P3497 Honda · Powertrain Honda's Variable Cylinder Management on the front cylinder bank didn't behave the way the PCM… Moderate

Subsystems

Fuel & Air Metering 193Emission Controls 97Ignition & Misfire 66Speed & Idle Control 57Transmission 57ECU & Outputs 54Hybrid / EV 14

Systems

Network 42Chassis 37Body 30