Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Fuel Pump Control - ERFS
The FP signal is a duty cycle command sent from the PCM to the FPDM. The FPDM uses the FP command to operate the fuel pump at the speed requested by the PCM or to turn the pump off. When the key is turned on, the electric fuel pump runs for about 1 second and is requested off by the PCM if engine rotation is not detected
| FP Duty Cycle Command | PCM Status | FPDM Actions |
|---|---|---|
| 0-4% | The PCM does not output this duty cycle. | Invalid FP duty cycle. The FPDM sends 25% duty cycle signal on the fuel pump monitor (FPM) circuit. The fuel pump is off. |
| 4-5% | Dead band range for transitions between FPDM states. | - |
| 5-45% | Normal operation. | The FPDM operates the fuel pump at the speed requested. "FP duty cycle" x 2 equals pump speed % of full on. (for example, FP duty cycle equals 42%. 42x2 equals 84. Pump is run at 84% of full on). The FPDM sends 50% duty cycle signal on FPM circuit. |
| 45-48% | Normal operation. An open circuit cannot be detected in this range. | The FPDM operates the fuel pump at the speed requested. "FP duty cycle" x 2 equals pump speed % of full on. The FPDM sends 50% duty cycle signal on FPM circuit. |
| 48-51% | Normal operation. | The FPDM operates the fuel pump at full on. The FPDM sends 50% duty cycle signal on FPM circuit. |
| 51-52% | Dead band range for transitions between FPDM states. | - |
| 52-68% | The PCM does not output this duty cycle. | Invalid FP duty cycle. The FPDM sends 25% duty cycle signal on the FPM circuit. The fuel pump is off. |
| 68-70% | Dead band range for transitions between FPDM states. | - |
| 70-81% | To request the fuel pump off, the PCM outputs this duty cycle. | Valid fuel pump off command from the PCM. The FPDM does not operate the fuel pump. The FPDM sends a 50% duty cycle signal on the FPM circuit. |
| 81-83% | Dead band range for transitions between FPDM states. | - |
| 83-100% | The PCM does not output this duty cycle. | Invalid FP duty cycle. The FPDM sends 25% duty cycle signal on the FPM circuit. The fuel pump is off. |
For additional information, refer to POWERTRAIN CONTROL HARDWARE , Fuel Pump Driver Module (FPDM).
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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