KOEO & KOER Codes
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2003 Ford RV Cutaway, 2003 Ford Econoline, 2003 Ford E550 Super Duty, 2003 Ford E450 Super Duty, and 2003 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
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 cluster 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, see DIAGNOSTIC TROUBLE CODE DEFINITIONS under QUICK TEST to find appropriate system test to perform.