Test P: Step 1

1) KOER Code 18: Check Computed Spark Timing  On TFI vehicles, Code 18 indicates SPOUT circuit is open. Possible causes for this fault are: open harness circuit or faulty ECA or TFI module.

On DIS vehicles, Code 18 indicates: SPOUT circuit is open or shorted to ground. Possible causes for this fault are: an open or shorted harness or faulty ECA or DIS module.

On EDIS vehicles, Code 18 indicates SAW circuit is either open or shorted to ground or VBAT. Possible causes for this fault are: an open or shorted harness or faulty ECA or EDIS module.

Perform KOER Self-Test and verify that Self-Test is activated. Check and record timing while in KOER Self-Test. Self-Test mode locks timing during testing and for a period of 2 minutes after last code is displayed. Computed timing during these 2 minutes is equal to base timing plus 20 degrees (+/-3 degrees). On 2.3L DIS Trucks, use exhaust side spark plug. If computed timing is correct, go to KOER Self-Test. If timing is not to specification, go to next step.