Key On Engine Running (KOER) Self Test

DESCRIPTION
Key On Engine Running (KOER) Self-Test is a functional test of the powertrain control system performed on-demand with the engine running and vehicle stopped. A check of the inputs and outputs is made during operating conditions and at normal temperature. A fault has to be present at the time of testing for the KOER Self-Test to detect the fault. When a fault is detected, a Diagnostic Trouble Code (DTC) will be output on the data link when requested by a scan tool. Technicians may be required to perform some action on certain vehicles during KOER in order to test some switches.

PROCEDURE
- Perform the necessary vehicle preparation and visual inspection.

- Select VEHICLE & ENGINE SELECTION.

- Select NEW VEHICLE YEAR & MODEL.

- Select year, engine, model with the appropriate qualifier, if needed (i.e., transmission, 49 State, California).

- Select DIAGNOSTIC DATA LINK.

- Select PCM - POWERTRAIN CTRL MODULE.

- Select KOER ON-DEMAND SELF-TEST.

- Start vehicle.

- Press START and TRIGGER.

- Follow operating instructions from the menu and perform BOO, 4X4L, and TCS cycling, if equipped.

- Press CANCEL to quit.