Key On Engine Off (KOEO) Diagnostic Test (Output State Test)

1994 PCED OBDI-A

SECTION 18A: Diesel Diagnosis — 7.3L DI Engine

3.: Key On Engine Off (KOEO) Diagnostic Test (Output State Test)

3.1 VEHICLE PREPARATION AND EQUIPMENT

Apply parking brake.
Place shift lever firmly in neutral.
Block drive wheels.
Connect Super STAR II to Data Link Connector (DLC) in order to run self-test.

Is vehicle prepared to run KOEO buzz test?

Yes	No
GO to Diagnostic Test Step 3.2.	REPEAT this test step.

3.2 KOEO OUTPUT STATE TEST

Note: Repeat as many times as necessary to check the operation of each component.

Turn key on/engine off.
Depress brake pedal once.
Wait approximately 5 seconds and depress brake pedal again.
Press and release accelerator pedal.

Note: The output state check test toggles the state of each output controlled by the PCM when the accelerator pedal is pressed and released. If the output was on, it will be toggled off, and vice versa.

Outputs affected are IDM-EN, FDCS, CID GPL, IPR, EPR duty cycle.
Note any output change in any of these systems.

Do the systems cycle from high to low voltage?

Yes	No
GO to component verification Diagnostic Test Step 3.3.	RERUN KOEO test to see what DTCs have been stored.

3.3 COMPONENT VERIFICATION TEST

Perform the EEC Pinpoint Test for each component that could cause the symptom.

Does each pinpoint test check OK?

Yes	No
All components check OK. RETURN to Performance Diagnostic Procedures.	SERVICE faults as indicated in pinpoint tests and RECHECK.