Diagnostic Strategy: Diagnostics

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. 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 DTCs.
Repair all non-transaxle codes first.
Repair all transaxle codes second.
Erase all continuous codes and attempt to repeat them.
Repair all continuous codes.
If only pass codes, proceed to diagnosis by symptom tables for further information and diagnosis.

By following the diagnostic sequence, the repair technician will be able to diagnose and repair the concern the first time.