ECU & Outputs Trouble Codes: List & Fixes

P06xx codes come from the engine or powertrain control module itself and from the output circuits it drives: internal memory or processor checks, sensor reference voltage and driver circuits for relays and actuators. Before condemning an expensive module, check battery condition, ground connections and fuses, and ask a dealer whether a software update exists. A replacement module often has to be programmed to the vehicle.

54Codes

2.9Average severity

15%High or critical

22%DIY-friendly

Severity distribution

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P0562 Powertrain The engine computer sees too little supply voltage – usually a charging, battery or ground… Moderate P0606 Powertrain The engine computer failed its own internal self-test – check its power and grounds before… Moderate P1000 Ford · Powertrain Ford's computer hasn't finished all its self-tests yet. It's a status message, not a fault. Minor P0219 Powertrain The engine was spun faster than its maximum allowed rpm, usually by a missed shift or wheelspin. Moderate P0690 Powertrain The ECM still sees power coming through its main relay when the relay should be off – often… Low P0217 Powertrain The engine overheated. Stop driving: continuing can warp the head, blow the head gasket… Critical

All codes (43)

All Severity 3+ Severity 4+

P1610 Nissan · Powertrain After repeated failed immobilizer checks, the Nissan ECM has locked itself and won't let… Moderate P1612 Nissan · Powertrain The Nissan ECM and the immobilizer (IMMU or BCM) couldn't complete their ID exchange, so… Moderate P1614 Nissan · Powertrain The Nissan immobilizer couldn't read the transponder chip in the key, so the engine isn't… Moderate P1626 Chevrolet · Powertrain The engine computer lost the 'OK to fuel' signal from the Chevy anti-theft system, so it may… Moderate P1631 Chevrolet · Powertrain The engine computer received the wrong anti-theft password, so it blocks starting or fuel. Moderate P1682 Chevrolet · Powertrain The engine computer's two ignition power feeds disagree, which can cause stalling or Reduced… High P1690 Hyundai · Powertrain The engine computer asked the SMARTRA immobilizer unit to check your key and got no answer back. Moderate P1693 Kia · Powertrain The immobilizer couldn't read a valid code from the chip in your Kia key, so the engine isn't… Moderate P2502 Powertrain The ECM distrusts the charging system – no output, wrong voltage or an implausible alternator… Moderate P2503 Powertrain The alternator can't reach the voltage the ECM asks for – usually a worn alternator or slipping… Moderate P2504 Powertrain The charging system is overcharging – too much voltage can boil the battery and damage… High P25A2 Chevrolet · Powertrain The brake module stored a fault and asked the engine computer to turn on the check engine light. Moderate P26B7 Ford · Powertrain The PCM sees an open circuit to the electric coolant bypass valve on Ford's 1.6L EcoBoost… Moderate

Subsystems

Fuel & Air Metering 193 Emission Controls 97 Ignition & Misfire 66 Speed & Idle Control 57 Transmission 57 Module Communication 43 Brakes, ABS & Chassis 36 Body Systems 31 Hybrid / EV 14