HF: Catalyst Efficiency Monitor And Exhaust — 2016 workshop reference 5156

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.

• Visually inspect the PCM connectors for damaged, or pushed out pins, corrosion and loose wires.

Are there any concerns with the wiring or the PCM connection?

Yes	No
REPAIR as necessary. Clear the PCM DTCs. CARRY OUT the catalyst monitor drive cycle to verify the repairs.	GO to HF4 .

Yes

REPAIR as necessary.

Clear the PCM DTCs. CARRY OUT the catalyst monitor drive cycle to verify the repairs.

GO to HF4 .

HF4 CHECK THE FUEL PRESSURE

WARNING: THE FUEL SYSTEM REMAINS PRESSURIZED WHEN THE ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE, USE CAUTION WHEN WORKING ON THE FUEL SYSTEM. REFER TO THE FUEL SYSTEM WARNING INFORMATION AT THE BEGINNING OF PINPOINT TEST HC. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.

Note: Fuel pressure above specification can produce an abnormally rich air to fuel mixture. This rich air to fuel mixture can cause higher than normal catalyst operating temperatures.

• Ignition ON, engine OFF.

• For Edge 2.0L, Edge 2.7L, Escape/Kuga 1.6L, Escape/Kuga 2.0L, Expedition, Explorer 2.3L, Explorer GTDI 3.5L, F-150 2.7L, F-150 3.5L GTDI, Fiesta 1.0L, Fiesta 1.6L GTDI, Flex GTDI

3.5L, Focus, Fusion 1.5L, Fusion 2.0L, MKC, MKS 3.5L, MKT 2.0L, MKT 3.5L, MKX 2.0L, MKX

2.7L, MKZ 2.0L, Mustang 2.3L, Navigator, Taurus 2.0L, Taurus 3.5L GTDI and Transit Connect

1.6L,

• Access the PCM and monitor the FLP (PRESS) PID.

• For mechanical returnless fuel systems (MRFS),

• Mechanical fuel pressure gauge connected.

• Start the engine. Record the fuel pressure.

• Compare the recorded fuel pressure reading to the Fuel System Specification Chart found at the beginning of Pinpoint Test HC. GO to Pinpoint Test HC .

• Ignition OFF.

Is the fuel pressure within specifications?

Yes	No
GO to HF5 .	GO to HC2 .

HF5 CHECK FOR LEAKS IN THE EXHAUST SYSTEM

Note: If a catalyst is in series with a leaking exhaust system, it can fail the catalyst efficiency monitor test.

• Inspect the exhaust system for the following:

◾ leaks ◾ cracks ◾ loose connections ◾ punctures ◾ aftermarket accessories or performance modifications

Is a concern present?

Yes	No

Source reference 5156

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.