KOEO & KOER Self-Tests

These DTCs indicate faults are present at time of testing. A hard fault may cause Malfunction Indicator Light (MIL) to illuminate and remain illuminated until fault is repaired. The MIL is located on instrument panel and may be labeled SERVICE ENGINE SOON or CHECK ENGINE. If KOEO or KOER DTCs are retrieved during KOEO ON-DEMAND SELF-TEST or KOER ON-DEMAND SELF-TEST, use DIAGNOSTIC TROUBLE CODE DEFINITIONS  to find appropriate system test to perform.