Engine Control Unit

Symptoms of Wear or Failure

  • Check Engine Light illuminates with codes that cannot be repaired
  • Several unrelated trouble codes are set simultaneously
  • Vehicle may not start or run
  • Poor engine performance
  • Engine stalls while driving

Related Repair Advice

  • Many vehicles have upgradeable software in their engine control units, so be sure to check for any Technical Service Bulletins (TSBs) that pertain to possible problems
  • When replacement is required, use a new factory ECU and install the latest software
  • An ECU can be mistakenly replaced when there was actually a defective engine sensor that was accidentally overlooked in the initial diagnosis