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DTC codes / Ford codes / P1233

P1233 · FordFuel Pump Driver Module Off-Line

P1233 on Ford vehicles indicates that the fuel pump driver module (FPDM) has stopped communicating with the powertrain control module (PCM) over the dedicated control area network (CAN) link. The PCM expects a periodic status message from the FPDM and sets this code when that message is missing for a calibrated time, meaning the module is either unpowered, internally failed, or the communication circuit is broken.

SystemPowertrain
Code typeFord specific
SeverityHigh
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Engine cranks but does not start because the fuel pump is not being commanded on
  • Engine starts and then stalls shortly after, or stalls intermittently while driving
  • No fuel pump prime sound when the key is turned to the run position
  • Reduced engine power or limp mode with the wrench light illuminated
  • Often no symptoms besides the warning light if the fault is intermittent and the module reconnects

Common causes, most likely first

  1. Corroded or failed fuel pump driver module, especially on models where it is mounted on the rear crossmember exposed to road spray
  2. Blown fuse or corroded fuse/relay contacts in the fuel pump driver module power circuit
  3. Damaged or chafed wiring between the FPDM and the fuel pump, or between the FPDM and the PCM
  4. Poor ground connection at the FPDM mounting bolts or chassis ground point
  5. Failed fuel pump causing excessive current draw that damages the driver module
  6. Water intrusion into the FPDM connector or module housing
  7. PCM internal fault or corrupted software affecting the communication bus

How to diagnose and fix it

  1. Verify battery voltage and check all fuses related to the fuel pump driver module and PCM power
  2. Inspect the FPDM connector and module for corrosion, water intrusion, or physical damage, especially on rear-mounted units
  3. Check for battery voltage at the FPDM power wire with the key on and confirm a good ground at the module mounting point
  4. Perform a wiggle test on the FPDM harness and communication wires while monitoring live data for FPDM status
  5. Use a scan tool to command the fuel pump on and verify that the FPDM responds and that pump current is within specification
  6. If communication is absent and power/ground are good, substitute a known-good FPDM and retest before condemning the PCM
  7. Repair or replace damaged wiring, terminals, or the FPDM as needed, then clear codes and verify the fuel pump prime and engine start

Why rear-mounted FPDMs fail so often

  • On many Ford trucks and SUVs the FPDM is mounted on the rear crossmember above the spare tire, where road salt and water collect and corrode the module and its connector.
  • A failed fuel pump can take out a new FPDM, so always check fuel pump current draw and resistance before replacing the module.
  • P1233 can be set by a simple blown fuse or a loose ground that also affects other circuits, so do not assume the module itself is bad.
  • Intermittent P1233 codes often appear only after driving over bumps or in wet weather, pointing to a wiring or connector issue rather than a failed module.
  • Some Ford models use a fuel pump control module that is separate from the fuel pump driver module, and misidentifying the module location leads to replacing the wrong part.

Can I keep driving with P1233?

Do not drive the vehicle with an active P1233 because the fuel pump may not run and the engine can stall without warning, creating a safety risk. If the engine starts and runs normally, drive only to a safe location for diagnosis and avoid highways or heavy traffic.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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