H: Fuel Control H: Introduction — 2016 workshop reference 5124

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.

H9 VACUUM LEAK REPAIR VERIFICATION

Note: If the freeze frame ECT or ECT1 PID is available, stabilize the engine at the temperature recorded by the freeze frame ECT or ECT1 PID. If the freeze frame ECT or ECT1 PID is not available, maintain the engine coolant temperature between 82°C - 101°C (180°F - 215°F) and the intake air temperature less than 46°C (115°F).

• Ignition ON, engine running.

• Access the PCM and monitor the SHRTFT1 (PER) and SHRTFT2 (PER) PIDs.

• Allow the engine to stabilize at the temperature necessary to recreate the concern.

• Record the SHRTFT1 and SHRTFT2 PID values.

• Ignition OFF.

• Repair the vacuum leak.

• Ignition ON, engine running.

• Allow the engine to stabilize at the temperature necessary to recreate the concern.

• Compare the recorded SHRTFT PID values, prior to the vacuum leak repair, to the current SHRTFT PID values.

Is the decrease in the SHRTFT PIDs greater than 15 percent?

Yes	No
RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM). REPEAT the self-test.	A vacuum leak is still present. GO to H8 .

Yes

RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM). REPEAT the self-test.

A vacuum leak is still present.

GO to H8 .

H10 CHECK THE UO2SPC CIRCUIT FOR AN OPEN

Note: Only the suspect universal HO2S needs to be diagnosed.

• Ignition OFF.

• Universal HO2S connector disconnected.

• PCM connector disconnected.

• Measure the resistance between:

( + ) Universal HO2S Connector, Harness Side	( - ) PCM Connector, Harness Side
UO2SPC	UO2SPC

Is the resistance less than 5 ohms?

Yes	No
GO to H11 .	REPAIR the open circuit. RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM). REPEAT the self-test.

Yes

GO to H11 .

REPAIR the open circuit.

RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM). REPEAT the self-test.

H11 CHECK THE FUEL PRESSURE

WARNING: WHEN CHECKING THE FUEL SYSTEM REMEMBER THAT THE FUEL SYSTEM MAY STILL BE PRESSURIZED WHEN THE ENGINE IS SWITCHED OFF. ALWAYS FOLLOW THE INSTRUCTIONS RELATED TO FUEL SYSTEM PRESSURE RELIEF. ALL FUEL HANDLING SAFETY PRECAUTIONS MUST BE OBSERVED. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.

Source reference 5124

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.