KOEO & KOER Self-Tests

These DTCs indicate faults are present at time of testing. A hard fault may cause CHECK ENGINE or Malfunction Indicator Light (MIL) to turn on and remain on until fault is repaired. If KOEO or KOER DTCs are retrieved during KOEO ON-DEMAND SELF-TEST or KOER ON-DEMAND SELF-TEST, diagnose affected DTC(s). See appropriate SELF- DIAGNOSTIC article in ENGINE PERFORMANCE.