P1398

Test 1 - 2:

Test 3 - 4:

SYMPTOM
P1398-MIS-FIRE ADAPTIVE NUMERATOR AT LIMIT

WHEN MONITORED
Under closed throttle decel with A/C off, ECT above 75, and more than 50 seconds after engine start.

SET CONDITION
One of the CKP sensor target windows has more than 2.86% variance from the reference window.

POSSIBLE CAUSES
- Adaptive numerator will not relearn
- Tone wheel/pulse ring inspection
- Wiring harness inspection
- Crankshaft position sensor