Key ON Engine OFF (KOEO) Self Test

IMPORTANT NOTES
- Ignition key MUST be cycled "OFF" for 10 seconds prior to the start of any KOEO or KOER self-test. If the key is not cycled off the system will not reset and the next test will not initiate correctly.
- Correct results of the quick tests are dependent on the proper operation of related non-EEC-IV components.
- Minor deviations from this procedure or the Flow of Diagnosis may cause false codes to be output.



KEY ON ENGINE OFF (KOEO) SELF-TEST PROCEDURE
1. Start engine and bring to normal operating temperature. If engine will not start or stalls after starting, proceed with next step.
2. Turn the key "OFF", then wait ten seconds.

Data Link Connector (DLC):

Analog Voltmeter Connection:

3. Activate the self test by grounding the Self-Test Input (STI) connector.
4. Turn the ignition key "ON".

Key On Engine OFF (KOEO) Diagnostic Trouble Code Format:

5. Record all codes received.
6. Turn ignition "OFF".


RESULTS, WHERE TO GO NEXT

- Record all codes received:
- Distinguish between ON DEMAND (hard) codes and CONTINUOUS MEMORY codes. On Demand codes are output first, followed by, a separator pulse, followed by Continuous Memory codes.
- Record the order in which they were received.

- If a pass code (111) is received for ON DEMAND (hard) codes, proceed to Timing Checks. Base Ignition Timing Check

- If any ON DEMAND (hard) codes are received, refer to Diagnostic Trouble Code Diagnostic Charts for appropriate testing procedures. Pinpoint Tests

NOTE: ON DEMAND (hard) codes should be diagnosed in the order they were received.

- Continuous memory codes recorded in this step will be used for diagnosis after ALL ON DEMAND (hard) codes from BOTH the KOEO and the KOER test have been corrected.