Vehicle applicability: This diagnostic supplement covers multiple Ford vehicles and engines. Follow the application named in the source below. Some references apply to vehicles other than Mustang.
HF: Catalyst Efficiency Monitor And Exhaust
HF: Introduction
Systems
HF1 CHECK FOR DTCS
Are DTCs P0420 or P0430 present?
Yes | No |
|---|---|
GO to HF2 . | For symptoms without DTCs, GO to HF6 . For all others, RETURN to Section 3 , Symptom Charts for further direction. |
HF2 CHECK FOR OTHER DTCS
Note: Internal deterioration of a catalytic converter is usually caused by abnormal engine operation upstream of the catalyst. Events that can produce higher than normal temperatures in the catalyst are particularly suspect. For example, misfiring can cause higher than normal catalyst operating temperatures.
Note: Make sure the customer has not noticed a high engine oil consumption. An engine that consumes oil at a high rate deposits high levels of phosphorus on the catalyst and reduces the catalyst efficiency.
• Carry out the PCM self-test.
Are any DTCs present other than DTCs P0420 or P0430?
Yes | No |
|---|---|
GO to Section 4, Diagnostic Trouble Code (DTC) Charts and Descriptions for pinpoint test direction and REPAIR the other DTCs first. Clear the PCM DTCs. REPEAT the self-test. | GO to HF3 . |
HF3 CHECK THE ELECTRONIC ENGINE CONTROL (EEC) WIRING HARNESS
Note: Check the HO2S electrical connectors to make sure the correct HO2S is connected to the correct electrical connector. The electrical connectors may be color coded to make sure the correct connection is made.
If the electrical connections of the rear HO2S are crossed, the catalyst efficiency monitor test fails.
• Visually inspect the HO2S harness connectors for any indication of crossed wiring.
• Visually inspect the harness for exposed wiring, corrosion and correct routing.
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.