What does it mean?
This code is set when the module measures a higher voltage on the fuel pump module B control circuit than the commanded state allows. When the driver is switched on the line should be pulled toward ground; if it stays near battery voltage instead, either the circuit is open so no current can flow, or something is feeding voltage into the line. Both conditions look the same to a smart driver that checks its output against what it expects, so this code covers an open circuit as well as a short to a supply. It is common to find it after work in the tank area, where a connector has not been reconnected properly. Whatever the cause, the second pump is not doing its job, and the fuel supply problems appear when demand is highest.
Symptoms
- MIL on with the second pump inactive
- Long cranking or a no-start when that pump is needed for pressure build-up
- Loss of power, hesitation or stalling at high load or with a low tank
- Fuel level readings that do not balance between the two halves of a saddle tank
- Engine cutting out on hills or during hard cornering
- No pump sound from the tank when the circuit is commanded on
Likely causes
- Open circuit in the control wire, including a broken conductor inside undamaged insulation
- Pump module connector not fully seated or a terminal backed out after a repair
- Internally open pump motor or driver, so the circuit cannot be pulled down
- Control wire shorted to battery voltage against another circuit in a damaged loom
- Corroded terminals adding so much resistance that the line no longer switches
- Poor ground at the pump module, which keeps the control line high
- Faulty output driver inside the control module, only after the harness is verified
How to fix it
- Command the pump with a scan tool while measuring the control circuit voltage at the pump connector
- Check the connector at the tank flange is fully latched and inspect for pushed-back or corroded terminals
- Test the control wire for continuity from the module to the pump connector and for a short to battery voltage
- Measure the pump module resistance across its terminals to see whether it is internally open
- Perform a voltage drop test on the pump ground while the circuit is commanded on
- Inspect the loom under the rear seat and along the floor for damage from previous repairs
- Repair the open or short, or renew the pump module when it is proven open, then verify the circuit switches correctly on command