Fuel Pump Monitor (FPM)
The fuel pump control module communicates diagnostic information to the PCM through the FPM circuit. This information is sent by the fuel pump control module as a duty cycle signal. The duty cycle signals that may be sent are listed in the following table.Fuel Pump Control Module Duty Cycle Signals
| Duty Cycle | Comments |
|---|---|
| 20% | This duty cycle indicates the fuel pump control module is receiving an invalid duty cycle from the PCM. |
| 60% | This duty cycle indicates the fuel pump control module is functioning normally. |
| 80% | This duty cycle indicates the fuel pump control module is detecting a concern with the secondary circuits. |
Fuel Filters
The system contains 3 to 5 filtering or screening devices.
- The fuel intake filter or screen is a fine nylon mesh filter mounted on the intake side of the fuel pump. It is part of the assembly and cannot be repaired separately.
- The filter/screen at the fuel rail port of the injectors is part of the fuel injector assembly and cannot be repaired separately
- The filter/screen at fuel inlet side of the fuel pressure regulator is part of the regulator assembly and cannot be repaired separately.
- The fuel filter assembly is located between the fuel pump and injectors. This filter may be a lifetime fuel filter located in the fuel pump assembly or an external 3 port inline filter that allows clean fuel to return to the fuel tank. A new filter may be installed for the external filter.
- The fuel filter sock is located on the fuel pump assembly between the reservoir and the fuel tank. The fuel filter sock is located on the fuel pump assembly between the reservoir and the fuel tank.