Diagnostic Strategy: Diagnostics

WARNING: This page is about a different car, the 2009 Mercury Sable, 2009 Ford Taurus X, and 2009 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

Carry out On-Board Diagnostic (OBD) 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 are obtained, refer to Diagnosis By Symptom for further information and diagnosis.

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