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
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
B0001
Body
The airbag module found a fault in the firing circuit for the driver's front airbag (stage 1).
High
C0035
Chassis
The ABS module lost a valid signal from the driver-side front wheel speed sensor.
Moderate
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
All codes (648)
P0327
Powertrain
Knock sensor 1's signal is too weak or pulled to ground: usually wiring, water or a loose…
Low
P0328
Powertrain
Knock sensor 1's signal is too strong: a short to voltage, electrical noise or a genuinely…
Low
P0330
Powertrain
The second knock sensor, usually the one for the bank without cylinder 1, has a circuit fault.
Low
P0332
Powertrain
Knock sensor 2 reads too low. On a V engine it's the bank without cylinder 1; on some fours…
Low
P0335
Powertrain
The engine computer lost the crankshaft position signal. Expect stalling or a crank-no-start.
High
P0336
Powertrain
Crank signal present but implausible: damaged teeth, a slipped balancer ring or debris confuse…
Moderate
P0337
Powertrain
The crank sensor signal line is stuck near 0 volts, usually a wire shorted to ground. Often…
High
P0338
Powertrain
The crank signal line sits at 5 or 12 volts and stops switching: open ground, open wire…
High
P0339
Powertrain
The crank signal drops out for moments at a time. Classic sign: stalls when hot, restarts once…
High
P0340
Powertrain
The computer lost the camshaft signal on bank 1. Expect long cranking, less power…
Moderate
P0341
Powertrain
The bank 1 cam signal lands at the wrong crank angle, often from a stretched chain or a sticky…
Moderate
P0342
Powertrain
The bank 1 cam sensor signal stays near 0 volts. Often a weak battery, a pinched wire…
Moderate
P0343
Powertrain
The bank 1 cam signal is stuck high: an unlatched connector, broken ground or open wire after…
Moderate
P0344
Powertrain
The bank 1 cam sensor signal keeps dropping out for short moments, which can cause random…
Moderate
P0345
Powertrain
The cam sensor on bank 2, the side without cylinder 1, has a missing or faulty signal on a V6…
Moderate
P0346
Powertrain
Bank 2's cam signal arrives out of position. On V6/V8s that often means a bank 2 chain, guide…
Moderate
P0350
Powertrain
The shared coil feed, ignition module or coil wiring is faulty. Often set with several…
Moderate
P0351
Powertrain
The engine computer found an electrical fault in coil A, the coil that fires cylinder 1 on most…
Moderate
P0352
Powertrain
Coil B, normally on cylinder 2, has a circuit fault. Where cylinder 2 sits depends…
Moderate
P0353
Powertrain
The circuit for coil C, which fires cylinder 3, failed its electrical check. Wiring is a big…
Moderate
P0354
Powertrain
Coil D, normally the one on cylinder 4, failed its circuit check. It often shows up right after…
Moderate
P0355
Powertrain
Coil E, the coil for cylinder 5, has an electrical fault. Only engines with five or more…
Moderate
P0356
Powertrain
The coil F circuit for cylinder 6 failed its check. On inline sixes it's the coil…
Moderate
P0357
Powertrain
Coil G, which fires cylinder 7 on V8s, has an electrical fault. On GM trucks it sits by…
Moderate
P0358
Powertrain
Coil H, for cylinder 8, has an electrical fault. On nearly every V8 it's the hardest coil…
Moderate
P0365
Powertrain
The exhaust cam sensor on bank 1 has lost its signal. Usually a heat-damaged sensor…
Low
P0366
Powertrain
Bank 1 exhaust cam signal is out of position: chain stretch, a sticky exhaust phaser…
Moderate
P0369
Powertrain
The bank 1 exhaust cam signal drops out now and then. Usually heat or vibration at the sensor…
Low
P0380
Powertrain
The diesel glow plug circuit A (relay, fuse, wiring or the plugs as a group) isn't drawing…
Low
P0381
Powertrain
The circuit for the dash wait-to-start light has a fault. The glow plugs themselves may still…
Minor