P1240 Fuel Pump Monitor Circuit Malfunction
The P1240 code indicates that the Powertrain Control Module (PCM) has detected a signal from the fuel pump control circuit that is outside the expected range. This Ford-specific code relates to the Fuel Pump Monitor (FPM) circuit, where the PCM expects a feedback signal confirming the pump's operational status. Instead, it receives a voltage or response that does not match programmed parameters. The FPM circuit allows the PCM to verify that the fuel pump is receiving power and functioning correctly when the fuel pump relay is activated.
01. Most Common Causes
- Faulty or damaged fuel pump relay
- Open or short circuit in the FPM wiring between the PCM and fuel pump
- Corroded or loose connectors in the fuel pump control circuit
- Defective fuel pump drawing excessive current
- Internal PCM failure (less common)
02. Symptoms You Will Notice
- Engine cranks but does not start
- Loss of power or hesitation during acceleration
03. Step-by-Step Diagnosis
Check for technical service bulletins (TSBs) related to the vehicle model
Inspect the fuel pump relay and replace if faulty
Test the Fuel Pump Driver Module (FPDM) for proper operation
Check wiring and connectors in the FPM circuit for damage, corrosion, or loose connections
Measure fuel pump current draw to determine if the pump is defective
If all else fails, test the PCM for internal faults
1. Frequently Asked Questions
Is it safe to drive?▼
No, driving with this code is not recommended as it can cause the engine to stall or fail to start, leading to a potential safety hazard.
How much does it cost to fix?▼
Repair costs typically range from $150 to $600, depending on the root cause (e.g., relay replacement is cheaper, while FPDM or fuel pump replacement is more expensive).