Diagnostic Strategy: Diagnostics

WARNING: This page is about a different car, the 2005 Mercury Montego, 2005 Ford Freestyle, and 2005 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.

Carry out on-board diagnostic procedures Key On/Engine Off (KOEO) and Key On/Engine Running (KOER).
Record all diagnostic trouble codes (DTCs).
Repair all non-transaxle DTC codes first.
Repair all transaxle DTC codes second.
Erase all continuous codes and attempt to repeat them.
Repair all continuous codes.
If only pass codes are obtained, go to DIAGNOSIS BY SYMPTOM for additional information and diagnosis.

Follow the diagnostic sequence to diagnose and repair the concern the first time.