OBD-II Trouble Codes: Meaning & Fixes
OBD-II trouble codes are five-character codes stored by your vehicle's computers when a monitored system goes out of range. Browse them by system (P, B, C, U), by sub-system or by the symptom you notice. Each code page explains what the code means, how serious it is, whether you can keep driving, the likely causes in order, how to diagnose it and what repairs typically cost.
648Codes
2.8Average severity
16%High or critical
18%DIY-friendly
Severity distribution
Most viewed
B0001
Body
The airbag module found a fault in the firing circuit for the driver's front airbag (stage 1).
High
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
All codes (104)
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
P1217
Nissan · Powertrain
Nissan's ECM saw engine coolant get hotter than it should, usually because the radiator fan…
Critical
P1285
Ford · Powertrain
Ford's cylinder head temperature sensor reports the engine is overheating. Pull over and shut…
Critical
P1295
Hyundai · Powertrain
Hyundai's engine computer no longer trusts the electronic throttle and has cut power as…
High
P1299
Ford · Powertrain
The engine got so hot that the Ford PCM is shutting off fuel to cylinders to save it. Stop…
Critical
P1326
Hyundai · Powertrain
Hyundai's KSDS software heard vibration typical of worn rod bearings and put the engine in limp…
Critical
P1326
Kia · Powertrain
Kia's engine computer detected early rod-bearing wear through the knock sensor and capped…
Critical
P1340
Volkswagen · Powertrain
The cam signal no longer lines up with the crank signal – often a jumped belt or stretched…
High
P1362
Honda · Powertrain
The PCM gets no signal at all from the top dead center (TDC) sensor; stalling or a no-start…
High
P1682
Chevrolet · Powertrain
The engine computer's two ignition power feeds disagree, which can cause stalling or Reduced…
High
P1735
Volkswagen · Powertrain
The DSG control unit lost a valid signal from the sensor that tracks clutch 1 and locks out…
High
P175D
Volkswagen · Powertrain
The DSG computer saw clutch 1 let go while it was supposed to stay engaged, so it cut…
High
P1778
Nissan · Powertrain
The Jatco CVT's step motor is being commanded, but the pulley ratio isn't following it as it…
High
P17F0
Nissan · Powertrain
The TCM detected judder it blames on the CVT itself, usually belt or pulley slip inside…
High
P2100
Powertrain
The computer can't push current through the throttle motor – the circuit to the throttle body…
High
P2104
Powertrain
A fail-safe has locked the engine at idle and the gas pedal no longer works – another code…
High
P2105
Powertrain
The engine computer shut the engine off on purpose because it could no longer control…
Critical
P2107
Powertrain
The processor supervising the electronic throttle failed its self-check – a computer fault, not…
High
P2111
Powertrain
The throttle plate stayed more open than commanded – a real safety concern until you know why.
High
P2112
Powertrain
The PCM asked the throttle to open, but it stayed shut – the engine can't get air, so it bogs…
High
P2146
Powertrain
The shared power feed for one group of injectors is open, so every injector in that group has…
High
P2149
Powertrain
The shared supply to the second injector group dropped out, often an intermittent wiring fault…
High
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
P2504
Powertrain
The charging system is overcharging – too much voltage can boil the battery and damage…
High
P3000
Toyota · Powertrain
Toyota's hybrid computer flags a fault in the high-voltage battery system and limits hybrid…
High
P3191
Toyota · Powertrain
The hybrid system spun the gas engine with its motor-generator, but the engine never fired up.
High