Key On Engine Running (KOER) On-Demand Self-Test
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2004 Ford RV Cutaway, 2004 Ford Pickup, 2004 Ford F550 Super Duty, 2004 Ford F450 Super Duty, and 2004 Ford Excursion. However, it is still accessible from the selected car via links, so may be relevant.
Key On Engine Running (KOER) On-Demand Self-Test is a functional test of the PCM performed on demand with the engine running. Temperature is not a factor, but A/C must be turned off. A check is made on the injection control pressure (ICP) variable geometry turbocharger (VGT), and exhaust gas recirculation (EGR) systems. During this test, engine RPM can vary. A fault must be present at the time of testing for the KOER On Demand Self-Test to detect a fault. If a fault is detected, a Diagnostic Trouble Code (DTC) will be the output on the data link at the end of the test when requested by a scan tool. Only a hard fault code (DTC) will be displayed.