Section 1 (Engine Controls - Tests W/Codes - 2.5L): Summary
WARNING: This page is about a different car, the 1990 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.
If no service codes (or pass code 11-1-11) are present, and a driveability problem still exists, proceed to H - "Engine Type" TESTS W/O CODES article for diagnosis by symptom (i.e. ROUGH IDLE, NO START, etc.), or intermittent diagnosis procedures.