Check engine light on: Codes, Causes & Fixes

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 P0113 Powertrain The intake air temperature signal is stuck at maximum voltage, which usually means an open… Low P0171 Powertrain The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees… Moderate P0172 Powertrain The engine computer is pulling as much fuel as it's allowed on bank 1 and the mixture is still… Moderate P0299 Powertrain The turbo or supercharger isn't building the boost pressure the engine computer is asking for. Moderate

P0868 Powertrain Measured transmission line pressure is below what the TCM commanded – clutches can slip… High P0884 Powertrain The transmission computer's power supply dropped out briefly – usually a battery, ground… Moderate P0887 Powertrain The circuit that switches the transmission power relay reads high voltage when it shouldn't. Moderate P0894 Powertrain The transmission computer measured slip inside the gearbox that shouldn't be there. Clutches… High P090C Ford · Powertrain The PowerShift TCM sees a low signal on the motor that works clutch B, the even-gear… Moderate P0A0F Powertrain The hybrid system spun the gas engine with its motor-generator to start it, but the engine… High P0A1F Powertrain The module that manages the high-voltage battery failed its self-check or reports implausible… Moderate P0A7E Powertrain The high-voltage battery got too hot. A clogged cooling intake or dirty fan is the usual cause. Moderate P0A7F Powertrain The battery computer has calculated that the whole high-voltage pack has worn past its usable… Moderate P0A80 Powertrain The hybrid system sees weak or unbalanced modules in the high-voltage battery and flags… Moderate P0A93 Powertrain The inverter's separate coolant loop isn't carrying heat away – usually a dead electric… High 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 P1128 Volkswagen · Powertrain VW's part-load fuel adaptation has maxed out adding fuel on bank 1 – the engine runs lean as… Moderate P1217 Nissan · Powertrain Nissan's ECM saw engine coolant get hotter than it should, usually because the radiator fan… Critical P1233 Ford · Powertrain The Ford PCM lost the status signal from the fuel pump driver module, so fuel pump control… Moderate P1259 Honda · Powertrain The PCM saw the VTEC solenoid or VTEC oil pressure switch misbehave on an older Honda VTEC… Moderate P1272 Nissan · Powertrain The front air/fuel ratio sensor on bank 1 isn't sending a usable, moving signal to the Nissan… Moderate P1285 Ford · Powertrain Ford's cylinder head temperature sensor reports the engine is overheating. Pull over and shut… Critical P1289 Ford · Powertrain The CHT sensor signal on your Ford is stuck near 5 volts, which the PCM reads as an impossibly… Moderate P1295 Hyundai · Powertrain Hyundai's engine computer no longer trusts the electronic throttle and has cut power as… High P1297 Volkswagen · Powertrain Boost is escaping between turbo and throttle body – usually a split hose or a leaking diverter… Moderate P1299 Ford · Powertrain The engine got so hot that the Ford PCM is shutting off fuel to cylinders to save it. Stop… Critical P1300 Toyota · Powertrain Toyota's ECM fires ignition coil No. 1 but gets no confirmation pulse (IGF) back from its… Moderate P1305 Toyota · Powertrain The igniter in Toyota coil No. 2 stops confirming its sparks, often only once the engine is hot. Moderate P1310 Toyota · Powertrain No spark confirmation from one Toyota coil: No. 3 on four-cylinders, but a different coil… Moderate P1320 Nissan · Powertrain The Nissan ECM isn't seeing the ignition primary signal it expects while the engine cranks… Moderate P1336 Ford · Powertrain The Ford PCM sees the cam and crank signals out of step, usually from a mistimed or worn cam… Moderate