What it means
Fuel pump module A does not respond as expected. 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 controls fuel-pump operation, and the engine control module checks whether the module's response matches the command. P025B sets when that response is outside the expected range or performance pattern, even if the circuit is not completely open.
Common causes
Most likely first.
- Module internal fault
- Sensor element aged beyond calibration window
- Sensor mounting loose - signal damping
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
- Record freeze-frame data and compare commanded and reported fuel-pump module operation with a scan tool.
- Inspect Module A's connector seals and harness for chafing, water ingress, corrosion, or a pin pushed back in the connector.
- With the code active, gently move the harness while watching module data to identify a vibration-sensitive connection fault.
- Check the module's supply, ground, and control circuit connections against the manufacturer's wiring information.
- If wiring checks pass, test the module and any associated feedback sensor or mounting for an out-of-range response or loose fit.
Common fixes
- Repair chafed wiring or restore a damaged connector seal.
- Reseat a pushed-back pin and clean corroded terminals.
- Secure the harness away from vibration or abrasion.
- Replace Fuel Pump Module A if its response remains out of range with verified wiring.
Can I keep driving?
Hard starting, stalling under load, or power loss can worsen and make acceleration unpredictable. Avoid heavy loads and stop driving if the engine stalls or cannot maintain power.
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.