Check engine light on: Codes, Causes & 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 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 P0135 Powertrain The heater inside the upstream oxygen sensor on bank 1 isn't working or its circuit is faulty. Low P0171 Powertrain The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees… Moderate

P1406 Ford · Powertrain The hose between Ford's DPFE sensor and the EGR-valve side of the orifice is off, leaking… Low P1441 Chevrolet · Powertrain Engine vacuum is reaching the fuel tank even though the PCM has the EVAP purge valve turned off. Low P1444 Nissan · Powertrain Nissan's ECM sees fuel vapor flowing to the engine while the purge valve is supposed to be shut. Low P144A Ford · Powertrain Ford's EVAP test pulled vacuum too fast, meaning part of the vapor path to the fuel tank… Low P1450 Ford · Powertrain Ford's EVAP test pulled vacuum on the fuel tank and the vacuum didn't bleed off as expected. Low P1451 Ford · Powertrain Ford's PCM sees an electrical fault in the circuit of the EVAP canister vent solenoid near… Minor P1456 Honda · Powertrain Honda's EVAP test found a vapor leak on the fuel tank side of the system. Low P1457 Honda · Powertrain Honda's EVAP self-test found a leak on the charcoal canister side, not at the fuel tank or gas… Low P1494 Jeep · Powertrain Your Jeep's EVAP leak detection pump was commanded to stroke, but its internal switch never… Minor P1495 Jeep · Powertrain The PCM found an open or short in the circuit that fires your Jeep's EVAP leak detection pump… Minor P1506 Ford · Powertrain Ford's idle speed stays above target even though the PCM has closed the idle air valve as far… Low P1507 Ford · Powertrain Ford's idle keeps dropping below target even with the idle air valve commanded wide open, often… Low P1516 Chevrolet · Powertrain The electronic throttle didn't move to where the computer commanded, so the engine drops into… Moderate P1518 Ford · Powertrain Ford's intake runner plates didn't close when commanded, so low-rpm torque suffers. Often… Low P1519 Honda · Powertrain The PCM found a fault in the idle air control valve (IACV) circuit on a Honda with a cable… Moderate P1529 Kia · Powertrain Your Kia's transmission computer found a fault and asked the engine computer to light the check… Moderate P1602 Volkswagen · Powertrain The engine computer saw its constant battery feed drop too low – usually a disconnected, flat… Low P1603 Toyota · Powertrain Toyota's ECM logged that the engine stopped by itself while running, without the key being… Moderate P1604 Toyota · Powertrain Toyota's ECM recorded a start that took too long, failed, or died within seconds of firing. Moderate P1605 Toyota · Powertrain On newer Toyotas the idle sagged below about 400 rpm; on some older ones it flags the ECM's… Low P1607 Honda · Powertrain The Honda engine computer's self-test found a fault inside its own circuitry. Moderate P1633 Ford · Powertrain Ford's PCM lost its constant battery feed, so the memory holding learned fuel, idle and shift… Low P1656 Toyota · Powertrain Toyota's ECM has found an open or short in the electrical circuit of the VVT-i oil control… Low P1682 Chevrolet · Powertrain The engine computer's two ignition power feeds disagree, which can cause stalling or Reduced… High P1698 Jeep · Powertrain The engine computer stopped hearing from the transmission computer, often leaving the Jeep… Moderate P1702 Ford · Powertrain Ford's gear selector position signal drops out now and then, so the PCM briefly loses track… Moderate 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 P17F1 Nissan · Powertrain The TCM caught a judder event it links to the CVT's control valve (valve body), not yet to belt… Moderate P1E00 Chevrolet · Powertrain Volt/Bolt pointer code: the hybrid/EV controller found a fault and asked for the check engine… Moderate