KOEO & KOER Codes (Hard Faults)

These codes indicate a hard fault that is actually present at the time of testing. These hard faults may cause the CHECK ENGINE or SERVICE ENGINE SOON light to illuminate and remain on until the fault is repaired. If KOEO or KOER codes are retrieved during the Self-Test, the KOEO or KOER code charts must be used to select the correct CIRCUIT TEST for testing and repair.