KOEO & KOER Codes (Hard Faults)

These codes indicate faults are present at time of testing. A hard fault may cause CHECK ENGINE light or MALFUNCTION INDICATOR LIGHT (MIL) to glow and remain on until fault is repaired. If KOEO or KOER codes are retrieved during KOEO SELF-TEST or KOER SELF-TEST, use CODE REFERENCE table under SERVICE CODE REFERENCE  to find correct testing and repair procedures.