P027AFuel Pump Module B Control Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- On demand-controlled fuel systems the engine module does not drive the pump itself but sends a pump control module the desired pump output on a separate control line, usually as a duty cycle; the module reports back on a monitor line or via CAN. Module B is a second pump module, for example on dual-tank commercial vehicles. P027A is the counterpart of P025A: the control line from the engine module to pump module B is open or faulty. No manufacturer using P027A was found – Ford reports line faults of both modules together under P025A, GM only uses P025A; the description follows CARB's circuit monitoring requirement and Ford's module B check. If the second tank's pump gets no valid command, fuel may run short when running from that tank.
- What you may notice
- Check engine light (manufacturer-dependent)
- Fuel shortage when running from the second tank
- Starting problems, surging
- Likely causes
- LikelyControl line to the pump module open or shorted, often along the frame
- LikelyConnector at the pump module corroded or wet (module often mounted on the frame)
- PossiblePump control module faulty (input)
- PossibleModule ground or supply poor
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.