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)
P1406
Ford · Powertrain
The hose between Ford's DPFE sensor and the EGR-valve side of the orifice is off, leaking…
Low
P1441
Chevrolet · Powertrain
Engine vacuum is reaching the fuel tank even though the PCM has the EVAP purge valve turned off.
Low
P1444
Nissan · Powertrain
Nissan's ECM sees fuel vapor flowing to the engine while the purge valve is supposed to be shut.
Low
P144A
Ford · Powertrain
Ford's EVAP test pulled vacuum too fast, meaning part of the vapor path to the fuel tank…
Low
P1450
Ford · Powertrain
Ford's EVAP test pulled vacuum on the fuel tank and the vacuum didn't bleed off as expected.
Low
P1451
Ford · Powertrain
Ford's PCM sees an electrical fault in the circuit of the EVAP canister vent solenoid near…
Minor
P1456
Honda · Powertrain
Honda's EVAP test found a vapor leak on the fuel tank side of the system.
Low
P1457
Honda · Powertrain
Honda's EVAP self-test found a leak on the charcoal canister side, not at the fuel tank or gas…
Low
P1494
Jeep · Powertrain
Your Jeep's EVAP leak detection pump was commanded to stroke, but its internal switch never…
Minor
P1495
Jeep · Powertrain
The PCM found an open or short in the circuit that fires your Jeep's EVAP leak detection pump…
Minor
P1506
Ford · Powertrain
Ford's idle speed stays above target even though the PCM has closed the idle air valve as far…
Low
P1507
Ford · Powertrain
Ford's idle keeps dropping below target even with the idle air valve commanded wide open, often…
Low
P1516
Chevrolet · Powertrain
The electronic throttle didn't move to where the computer commanded, so the engine drops into…
Moderate
P1518
Ford · Powertrain
Ford's intake runner plates didn't close when commanded, so low-rpm torque suffers. Often…
Low
P1519
Honda · Powertrain
The PCM found a fault in the idle air control valve (IACV) circuit on a Honda with a cable…
Moderate
P1529
Kia · Powertrain
Your Kia's transmission computer found a fault and asked the engine computer to light the check…
Moderate
P1602
Volkswagen · Powertrain
The engine computer saw its constant battery feed drop too low – usually a disconnected, flat…
Low
P1603
Toyota · Powertrain
Toyota's ECM logged that the engine stopped by itself while running, without the key being…
Moderate
P1604
Toyota · Powertrain
Toyota's ECM recorded a start that took too long, failed, or died within seconds of firing.
Moderate
P1605
Toyota · Powertrain
On newer Toyotas the idle sagged below about 400 rpm; on some older ones it flags the ECM's…
Low
P1607
Honda · Powertrain
The Honda engine computer's self-test found a fault inside its own circuitry.
Moderate
P1610
Nissan · Powertrain
After repeated failed immobilizer checks, the Nissan ECM has locked itself and won't let…
Moderate
P1612
Nissan · Powertrain
The Nissan ECM and the immobilizer (IMMU or BCM) couldn't complete their ID exchange, so…
Moderate
P1614
Nissan · Powertrain
The Nissan immobilizer couldn't read the transponder chip in the key, so the engine isn't…
Moderate
P1626
Chevrolet · Powertrain
The engine computer lost the 'OK to fuel' signal from the Chevy anti-theft system, so it may…
Moderate
P1631
Chevrolet · Powertrain
The engine computer received the wrong anti-theft password, so it blocks starting or fuel.
Moderate
P1633
Ford · Powertrain
Ford's PCM lost its constant battery feed, so the memory holding learned fuel, idle and shift…
Low
P1656
Toyota · Powertrain
Toyota's ECM has found an open or short in the electrical circuit of the VVT-i oil control…
Low
P1682
Chevrolet · Powertrain
The engine computer's two ignition power feeds disagree, which can cause stalling or Reduced…
High
P1684
Jeep · Powertrain
An informational code: your Jeep's PCM lost battery power at some point in the last 50 engine…
Minor