P1237 Fuel Pump Speed Control Circuit
P1237 is a Ford-specific diagnostic trouble code indicating a malfunction in the fuel pump speed control circuit. The Powertrain Control Module (PCM) commands a specific fuel pump speed via pulse-width modulation (PWM) to the Fuel Pump Driver Module (FPDM). The FPDM uses an internal Hall effect sensor to monitor actual pump speed and reports it back to the PCM. When the PCM detects a persistent mismatch between commanded and actual pump speed, it sets code P1237.
01. Most Common Causes
- Faulty Fuel Pump Driver Module (FPDM)
- Worn or obstructed fuel pump unable to reach commanded speed
- Damaged or corroded wiring between PCM and FPDM
- Bent, corroded, or loose pins in FPDM connectors
- Excessive resistance in PWM control or feedback circuit
- Internal PCM failure in FPDM control circuit
- Clogged fuel filter causing excessive pump load
02. Symptoms You Will Notice
- Engine may crank but not start
- Reduced engine performance or hesitation during acceleration
03. Step-by-Step Diagnosis
Scan for codes and verify P1237 is present
Inspect FPDM connector for corrosion, bent pins, or damage
Test FPDM power and ground circuits
Check fuel pump operation and measure actual pump speed vs commanded
Test PWM signal from PCM to FPDM with oscilloscope
Inspect fuel filter for restriction and replace if clogged
1. Frequently Asked Questions
Is it safe to drive?▼
No, driving with P1237 is not recommended as it can cause stalling, poor performance, or complete engine shutdown, posing a safety risk.
How much does it cost to fix?▼
Repair costs typically range from $200 to $800, depending on whether the FPDM, fuel pump, or wiring needs replacement.