OBD-II Trouble Codes: Meaning & Fixes

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

P2188 Powertrain At idle, bank 1 gets extra fuel from somewhere the PCM doesn't control; above idle the mixture… Moderate P2195 Powertrain The front O2 or air-fuel sensor keeps reading lean while the rear sensor shows the engine isn't… Low P2196 Powertrain The front sensor on bank 1 keeps claiming rich, so the PCM strips out fuel the engine actually… Low P2197 Powertrain The upstream sensor on the bank without cylinder 1 reads lean while the other checks say that… Low P2198 Powertrain Bank 2's front sensor keeps claiming rich, so the PCM leans out that side of the engine more… Low P219A Powertrain One cylinder on bank 1 runs clearly richer or leaner than the others, even if the average looks… Moderate P219B Powertrain One cylinder on bank 2 runs off the mixture of the other cylinders on that side of the engine. Moderate P2200 Powertrain The engine computer lost a usable signal from the NOx sensor ahead of the SCR catalyst on bank… Moderate P2201 Powertrain The upstream NOx sensor still communicates, but its readings don't match what the ECM expects. Moderate P2202 Powertrain The upstream NOx sensor reports a signal or internal circuit below its lower limit. Moderate P2203 Powertrain The upstream NOx sensor reports a value or circuit stuck above its upper limit. Moderate P2204 Powertrain The upstream NOx sensor signal keeps dropping out or jumping around for short moments. Low P2209 Powertrain The heater in the upstream NOx sensor can't reach or hold its working temperature properly. Low P2226 Powertrain The engine computer can't get a valid reading from its barometric (ambient air pressure) sensor. Low P2227 Powertrain The baro sensor's reading doesn't agree with the other pressure sensors or with what the engine… Low P2228 Powertrain The baro sensor signal is below its valid range, as if the car were far higher than any road… Moderate P2237 Powertrain The wire that carries the pump current of the upstream wideband (air-fuel) sensor is open. Low P2238 Powertrain The pump-current wire of the upstream air-fuel sensor is being pulled low, usually by a short… Low P2243 Powertrain The ECM lost the reference-cell signal of the upstream wideband sensor, as if the wire were… Low P2262 Powertrain The engine computer commanded boost but saw almost none, pointing to a mechanical turbo… Moderate P2263 Powertrain Boost isn't tracking its target closely enough: too low, too high or too slow to respond. Moderate P2270 Powertrain The oxygen sensor after the catalytic converter won't show rich, even when the PCM deliberately… Low P2271 Powertrain The sensor after the converter stays rich even while coasting with the fuel cut off, when it… Low P2279 Powertrain Air is getting into the engine after the mass airflow sensor, so the computer isn't measuring… Low P2293 Powertrain The second fuel pressure control stage can't hold its target; on VW/Audi 2.0T often… Moderate P229F Powertrain The NOx sensor after the SCR catalyst is sending believable-looking but wrong or sluggish… Moderate P2400 Powertrain The engine computer can't drive the EVAP leak detection pump – usually a broken wire, bad plug… Low P2401 Powertrain The leak detection pump's control wire reads too low – most often a wire rubbing through… Low P2401 Toyota · Powertrain In Toyota's key-off EVAP test, the canister module's leak detection pump didn't pull… Low P2402 Powertrain The leak pump's control line reads too high – usually a short to a 12-volt wire… Low