Poor power or earth supply to the fuel pump driver module, including corroded or loose connections; Damaged wiring or a faulty connector between the PCM and the module; Blown fuse or faulty relay supplying the fuel pump circuit; Faulty fuel pump driver module; Fuel pump drawing excessive current or shorted, overloading the module; Corrosion or water ingress at the module, often on models where it is mounted in an exposed location; Internal PCM fault or outdated software.

P1233

Fuel Pump Driver Module Off-Line.

Ford
Powertrain
Manufacturer code
High severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
2: AreaFuel and air metering (injector circuit)
33: FaultThe specific fault in that area

What it means

P1233 on a Ford means the powertrain control module has lost communication with, or has not received a valid signal from, the fuel pump driver module (FPDM). The FPDM controls fuel pump speed and voltage on many Ford models, so if the PCM sees it as off-line it can no longer confirm that the pump is being controlled correctly. Layout, wiring and module location vary by model and year.

Symptoms

Engine cranks but will not start
Engine starts then stalls or cuts out
Intermittent loss of power or hesitation under load
Fuel pump silent when the ignition is switched on
Engine warning light on
Long cranking or intermittent no-start when hot

Possible causes

Poor power or earth supply to the fuel pump driver module, including corroded or loose connectionslikely
Damaged wiring or a faulty connector between the PCM and the modulelikely
Blown fuse or faulty relay supplying the fuel pump circuitpossible
Faulty fuel pump driver modulepossible
Fuel pump drawing excessive current or shorted, overloading the modulepossible
Corrosion or water ingress at the module, often on models where it is mounted in an exposed locationpossible
Internal PCM fault or outdated softwarerare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including whether other fuel or communication codes are present
Check the relevant fuses and relays for the fuel pump circuit against the wiring diagram for the specific model
Inspect the fuel pump driver module, its connector and nearby wiring for corrosion, water ingress, heat damage or chafing
Check for correct battery voltage and a good earth at the module connector with the ignition on, following the model's wiring diagram
Check continuity and insulation of the signal wires between the PCM and the module for open circuit, short to earth or short to power
Listen for the fuel pump priming on ignition on and check fuel pressure against the specification for the engine
Check the fuel pump current draw to see whether a failing pump is overloading the module
Check for any applicable software updates or technical bulletins for the model and engine

How to fix

Clean, tighten or repair the power and earth connections to the module
Repair or replace damaged wiring or connectors in the module circuit
Replace the blown fuse or faulty relay, and find out why it failed
Replace the fuel pump driver module if it is confirmed faulty
Replace the fuel pump if it is drawing excessive current, then recheck the module
Update the PCM software if an outdated calibration is a known cause for the vehicle

Can I keep driving?

High severity

Avoid driving the car, as it may stall without warning or fail to restart, which is a safety risk in traffic. Have the fault diagnosed and repaired before using the vehicle normally.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.