Key On Engine Running (KOER) On-Demand Self-Test

The KOER on-demand self-test is a functional test of the PCM carried out on-demand with the key on, the engine running and the vehicle stopped. A check of certain inputs and outputs is made during operating conditions and at a normal operating temperature. The brake pedal position, transmission control, and power steering tests are part of the KOER on-demand self-test and must be carried out during this operation if applicable. These are described below. A fault must be present at the time of testing for the KOER on-demand self-test to detect the fault. When a fault is detected, a DTC is output on the data link at the end of the test as requested by a diagnostic tool.