P1235
Fuel Pump Control Out of Range
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The P1235 is a Ford-specific code indicating that the Fuel Pump Driver Module (FPDM) has detected an invalid or missing fuel pump control signal from the Powertrain Control Module (PCM). The FPDM relies on a duty cycle signal from the PCM to control fuel pump speed — when this signal is out of the expected range, the FPDM enters a diagnostic mode and may reduce or cut fuel delivery.
This code frequently appears alongside P1233 and can cause similar symptoms: stalling, hard starting, or a complete no-start condition. The FPDM is the most common failure point, as it is mounted in an exposed location underneath the vehicle where it is vulnerable to corrosion and physical damage. Wiring issues between the PCM and FPDM are the second most common cause.
Because this code can cause the engine to stall while driving, it should be treated as a high-priority repair. Start by inspecting the FPDM connector and wiring for corrosion or damage. Test the duty cycle signal from the PCM with a multimeter or scan tool. If the wiring is intact, the FPDM itself likely needs replacement. The module typically costs $60–$150 for parts and is accessible from underneath the vehicle.
Severity
Symptoms
- •Engine stalls or dies while driving
- •Difficulty starting the vehicle
- •Poor acceleration and reduced power
- •Engine sputters at higher RPMs
- •Reduced fuel efficiency
Likely Causes
The FPDM is not receiving a valid control signal from the PCM or is outputting a 25% duty cycle diagnostic signal, indicating the fuel pump control is out of its operating range.
Open, shorted, or corroded wiring in the circuit between the Powertrain Control Module and the Fuel Pump Driver Module prevents proper signal communication.
A fuel pump drawing excessive current or providing inconsistent pressure can cause the FPDM to report out-of-range values.
The Powertrain Control Module may not be sending the correct duty cycle signal to the FPDM due to a software glitch or poor ground.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Replace the Fuel Pump Driver Module (FPDM)
- Inspect and repair wiring and connectors between the PCM and FPDM
- Replace the fuel pump if it is drawing excessive current
- Check and clean ground connections for the FPDM and PCM