What it means
Fuel pump module B 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 B is the second pump module in a system that uses more than one pump or module. The control module monitors module B's control response and sets this code when that response is outside the expected range or performance; it does not by itself identify a failed pump or sensor.
Common causes
Most likely first.
- Module B 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
- Review freeze-frame data and live module B command, feedback, and fuel-pressure data to identify the conditions when its response goes out of range.
- Inspect module B's connector, wiring, and mounting for chafing, water intrusion, loose terminals, or poor contact.
- With the fault active, check whether gently moving the accessible harness changes module B's signal or operation, then inspect any affected section closely.
- Test the module B circuit and its feedback signal using vehicle-specific wiring information and the manufacturer's procedure.
- If the circuit and connections are sound, test module B and any associated sensor or mounting condition against the manufacturer's specification.
Common fixes
- Dry, clean, and reseal a water-affected module B connector as appropriate.
- Repair chafed wiring or loose or pushed-back connector terminals.
- Secure a loose module B or associated sensor mounting.
- Replace module B or its sensor only if testing confirms it is faulty.
Can I keep driving?
Avoid heavy acceleration and driving that could leave you stranded if fuel delivery falters. If the engine stalls, will not start, or loses power, stop driving and arrange repair.
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.