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.
Description and Operation 1-75
Fuel Systems
Typical Mechanical Returnless Fuel System (MRFS)
Fuel Pump Control — All Others
NOTE: The Focus 2.3L uses 2 fuel pump control modules to control fuel for the fuel delivery system. The PCM sends one FP duty cycle on the FPC circuit. Both fuel pump control modules use this circuit.
The FP signal is a duty cycle command sent from the PCM to the fuel pump control module. The fuel pump control module uses the FP command to operate the fuel pump at the speed requested by the PCM or to turn the fuel pump OFF. A valid duty cycle to command the fuel pump ON, is in the range of 15-47%. The fuel pump control module doubles the received duty cycle and provides this voltage to the fuel pump as a percent of the battery voltage. When the ignition is turned ON, the fuel pump runs for about 1 second and is requested OFF by the PCM if engine rotation is not detected.
Fuel Pump Duty Cycle Output From PCM (Focus 2.0L GDI)
FP Duty Cycle Command | PCM Status | Fuel Pump Control Module Actions |
|---|---|---|
0-4% | Valid OFF duty cycle. | The fuel pump control module sends a 60% duty cycle signal on the FPM circuit. The fuel pump is OFF. |
4-18% | Invalid OFF duty cycle. | The fuel pump control module sends a 20% duty cycle signal on the FPM circuit. The fuel pump is OFF. |
18-80% | Normal operation. | The fuel pump control module operates the fuel pump at the speed requested. FP duty cycle times 1.43 minus 14.29 equals pump speed % of full ON. For example, FP duty cycle equals 42%. 42 times 1.43 minus 14.29 equals 46 (rounded). Pump is run at 46% of full ON. The fuel pump control module sends a 60% duty cycle signal on the FPM circuit. |
80-86% | Normal operation. | The fuel pump control module operates the fuel pump at full ON. The fuel pump control module sends a 60% duty cycle signal on the FPM circuit. |
86-95% | Invalid OFF duty cycle. | The fuel pump control module sends a 20% duty cycle signal on the FPM circuit. The fuel pump is OFF. |
95-100% | Valid OFF duty cycle. | The fuel pump control module sends a 60% duty cycle signal on the FPM circuit. The fuel pump is OFF. |
2016 Powertrain Control/Emissions Diagnosis, Gasoline Engines, 3/2015
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.