Key ON Engine Running (KOER) Self-Test

IMPORTANT NOTES

- Ignition key MUST be cycled "OFF" for 10 seconds prior to the start of any Key On Engine Off (KOEO) or Key On Engine Running (KOER) self-test. If the key is not cycled off the system will not reset and the next test will not initiate correctly.

- Prior to starting this test the engine must be hot. If the warm-up procedure is not followed false trouble codes will be set (oxygen sensor, coolant temperature, and in-range sensor failure codes).

- Minor deviations from this procedure or the Flow of Diagnosis may cause false codes to be output.

- If the engine starts but stalls, or stalls during self test, refer to pinpoint test step S2. S2 - Check For RPM Drop




KEY ON ENGINE RUNNING (KOEO) SELF-TEST
1. Warm engine at 2,000 rpm for two minutes.
2. Turn the engine "OFF" and wait for ten seconds
3. Activate the self test by grounding the Self-Test Input (STI) connector.

Data Link Connector (DLC):

Analog Voltmeter Connection:

Key On Engine Running (KOER) Diagnostic Trouble Code Format:

4. Start the engine.
5. After the engine ID code is received:
- Depress and release the brake pedal,
- Turn the steering wheel 1/2 turn and release it.
- If the vehicle is equipped with an E4OD transmission cycle the Overdrive Cancel Switch (OCS).
6. When the dynamic response "goose" code appears, briefly go to wide open throttle.
7. Record all codes displayed.
8. Turn "OFF" the engine and deactivate the self test.

RESULTS, WHERE TO GO NEXT

- Engine diagnostic trouble code 998 indicates vehicle is in Failure Mode Effects Management (FMEM). The KOER test can't be performed while in FMEM and the results are invalid. Rerun KOEO self test and correct all fault codes. Key On Engine Off (KOEO) Self Test


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

NOTE: ON DEMAND (hard) codes should be diagnosed in the order they were received, unless DTC 213 is output. If KOER code 213 is present disregard all other codes and diagnose DTC 213 first.


- If a pass code (111) was received in the KOER test (meaning there are no ON DEMAND (hard) codes present), then refer to Diagnostic Trouble Code Charts and Descriptions and address any CONTINUOUS MEMORY CODES received during the KOEO test. Manufacturer Code Charts


- If a pass code (111) was received in the KOER test and there were no CONTINUOUS MEMORY CODES received during the KOEO test then refer to Diagnosis by Symptom.