What it means
Fuel pump module A control voltage below expected range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Fuel Pump Module A receives a control signal from the engine control module to regulate fuel-pump operation. P025C sets when the monitored control-circuit voltage is lower than expected, which can prevent the module from responding correctly.
Common causes
Most likely first.
- Wiring shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light on
- Hard start, no start, or stalling under load
- Power loss especially at high load or rpm
- Possible long cranking time
How to diagnose it
- Capture freeze-frame data and scan-tool fuel-pump command data to establish when the low-signal fault occurs.
- Inspect Module A's control wiring for chafing, insulation damage, or contact with ground, and check its connector for corrosion.
- Check for a short to ground in the control wire using the manufacturer's wiring diagram and test procedure.
- Measure the control signal at the module connector while commanding the pump, and compare it with the manufacturer's specification.
- If the harness and connector pass, test the module and its supply and ground circuits for an internal fault.
Common fixes
- Repair chafed control wiring that is contacting ground.
- Clean or replace corroded connector terminals.
- Repair damaged insulation and secure the harness away from grounded surfaces.
- Replace Fuel Pump Module A if the low signal persists with verified wiring and connections.
Can I keep driving?
The low control signal can cause hard starting, stalling, or power loss under load. Avoid driving if the vehicle stalls or loses power in traffic, as fuel delivery may become unreliable.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.