P027BFuel Pump Module B Control Circuit Range/Performance
- 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. P027B means pump module B receives an invalid command or its feedback does not match. Ford's module signals this with a 20 % (±4 %) duty cycle on its monitor line, checked continuously at 11–16 V over 2–5 s; on Ford commercial vehicles the module B monitor line runs via the smart relay module and CAN to the engine module. Whether the warning light comes on depends on the vehicle.
- What you may notice
- Check engine light (vehicle-dependent)
- Fuel shortage when running from the second tank
- Surging, lack of power
- Likely causes
- LikelyContact resistance or corrosion in the control or monitor line to module B
- PossiblePump control module B faulty
- PossibleGround problems
- RareRelay module or CAN forwarding disturbed (Ford commercial vehicles)
- 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.