Honda OBD Codes: Meaning & Fixes

P0420 Powertrain The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. Low P0172 Powertrain The engine computer is pulling as much fuel as it's allowed on bank 1 and the mixture is still… Moderate P0300 Powertrain The engine computer sees misfires that jump between cylinders or hit several cylinders at once. High P0302 Powertrain Cylinder 2 keeps misfiring. On inline engines it's a middle cylinder, so rule out coolant… Moderate P0303 Powertrain Cylinder 3 is misfiring. Check whether it misses at idle or under load before you blame… Moderate P0304 Powertrain Cylinder 4 is misfiring. Its end or rear position makes water, oil and intake leaks common… Moderate

P0000 Powertrain P0000 is not a fault: the scanner found no stored code. It is a placeholder that means… Minor P0012 Powertrain The bank 1 intake cam lags behind the angle the PCM wants, often from chain stretch or weak oil… Moderate P0087 Powertrain Measured fuel pressure has dropped well below what the engine computer is asking for. High P0152 Powertrain Bank 2's front O2 sensor is pinned high – usually voltage leaking in from its heater wire… Moderate P0172 Powertrain The engine computer is pulling as much fuel as it's allowed on bank 1 and the mixture is still… Moderate P0300 Powertrain The engine computer sees misfires that jump between cylinders or hit several cylinders at once. High P0301 Powertrain Cylinder 1 is repeatedly failing to fire. The cause is almost always its coil, plug, injector… Moderate P0302 Powertrain Cylinder 2 keeps misfiring. On inline engines it's a middle cylinder, so rule out coolant… Moderate P0303 Powertrain Cylinder 3 is misfiring. Check whether it misses at idle or under load before you blame… Moderate P0304 Powertrain Cylinder 4 is misfiring. Its end or rear position makes water, oil and intake leaks common… Moderate P0401 Powertrain The ECU opened the EGR system but saw too little effect — the valve or its passages are likely… Low 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 P0457 Powertrain The EVAP leak test found the system wide open — almost always a loose, missing or worn gas cap. Minor P0505 Powertrain The engine computer can't hold idle speed where it wants it – usually a dirty or sticking idle… Low P0720 Powertrain Electrical fault in the output shaft speed signal – shift timing and sometimes the speedometer… Moderate P0733 Powertrain Third gear slips: input shaft speed doesn't match output speed times the 3rd-gear ratio. Moderate P0735 Powertrain Fifth gear slips or isn't fully applied; the TCM measures a ratio that doesn't fit 5th. Moderate P0741 Powertrain The torque converter lockup clutch slips or won't engage when the computer commands it. Moderate P0751 Powertrain Solenoid A is wired fine but its valve isn't doing its job, so gears are missing – often stuck… High P0753 Powertrain The control circuit for shift solenoid A reads open, shorted or out of range – an electrical… Moderate P0776 Powertrain Pressure control solenoid B isn't delivering the pressure the TCM asks for – harsh or slipping… Moderate P0780 Powertrain A gear change didn't complete the way the TCM expected, but it can't pin the fault to one part. Moderate P1157 Honda · Powertrain The signal lines of Honda's upstream air/fuel ratio sensor read too high, usually an open… Low P1166 Honda · Powertrain The circuit that powers the heater in Honda's upstream A/F sensor is open, shorted or unpowered. Low P1167 Honda · Powertrain The upstream A/F sensor heater is powered but isn't drawing the current or heating the sensor… Low P1259 Honda · Powertrain The PCM saw the VTEC solenoid or VTEC oil pressure switch misbehave on an older Honda VTEC… Moderate P1298 Honda · Powertrain The ELD signal that tells the PCM how much current the car is drawing is stuck too high. Low P1361 Honda · Powertrain The top dead center (TDC) sensor signal keeps dropping out for a moment while the engine… Moderate P1362 Honda · Powertrain The PCM gets no signal at all from the top dead center (TDC) sensor; stalling or a no-start… High