What does it mean?
This code covers the control circuit of fuel pump module B, the second pump or pump driver in the fuel supply system. Vehicles use a second module for different reasons: a saddle-shaped tank with a transfer pump in the opposite half, a staged pump that only runs at high demand, or a separate driver that varies pump speed to match consumption. The control module switches or modulates this circuit and monitors the output for a plausible electrical state. When it detects an open circuit, or no feedback at all from the driver, this fault is stored. Depending on the design the vehicle may run normally at light load and only starve for fuel when demand is high or the tank is low.
Symptoms
- MIL on, often with no complaint at all under light driving
- Long cranking or a no-start condition when the second pump is needed for priming
- Fuel starvation, hesitation or power loss at high load or high speed
- Stalling on corners or braking when the tank is low, on vehicles with a saddle tank and a transfer pump
- Fuel gauge behaving oddly on vehicles where the two halves of the tank cannot equalise
- Engine cutting out and restarting after a short pause
Likely causes
- Broken or disconnected control wire between the module and the pump, often at the connector above the tank
- Corroded connector at the tank flange, which is exposed to moisture and road salt
- Blown fuse or a failed relay in the pump supply circuit
- Internally open pump motor or driver inside the module, so no load is present for the driver to see
- Poor or corroded ground at the pump module
- Harness damage caused during a previous tank or fuel pump repair
- Failed output driver inside the control module, only accepted after the circuit tests good
How to fix it
- Read the freeze frame to see the load, speed and fuel level at the moment the fault set
- Command the pump module on with a bidirectional scan tool and listen at the tank filler or the access panel
- Check the fuse and relay for that circuit and confirm supply voltage at the pump connector with the circuit commanded on
- Measure the control circuit for continuity from the module to the pump, and check the ground with a voltage drop test
- Back-probe the control wire with a meter or a scope to see whether the driver is actually switching
- Inspect the connector at the tank flange for corrosion, water and pushed-out terminals
- Repair the harness or replace the pump module as the tests direct, and consider the driver module only when everything else is proven