KOEO & KOER Self-Test Description (Hard Faults)
WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 1996 Ford RV Cutaway, 1996 Ford Pickup, 1996 Ford F-Super Duty, 1996 Ford Econoline, and 1996 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
Key On Engine Off (KOEO) self-test or Key On Engine Running (KOER) self-test are functional tests of powertrain control system performed with key on and engine off. These DTCs indicate faults are present at time of testing (with exception of IDM DTCs). During KOER self-test, PCM performs Injection Control Pressure (ICP) and Exhaust Back Pressure (EBP) system function. A hard fault may cause CHECK ENGINE or Malfunction Indicator Light (MIL) to go on and remain on until fault is repaired. When a fault is detected, a DTC will be output on data link when requested by a scan tool. If KOEO DTCs or KOER DTCs are retrieved during KOEO or KOER self-tests, use DIAGNOSTIC TROUBLE CODE IDENTIFICATION for appropriate pinpoint test to perform.