P20FDReductant Pump B Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P20FD indicates that the control line of reductant pump B sits too high, for instance shorted to battery voltage, so the controller can no longer regulate the pump properly. No limits are published for pump B. Ford's 2023 diesel summary sets the matching pump A fault (P208D) when pump voltage exceeds 16 V or controller current passes 5 A while the driver is on, confirmed within about 2 seconds, which is quicker than the 8 seconds used for open and low faults. Ford is the only maker that documents P20FD itself: 2023–2024 Super Duty and F-650/F-750 trucks with the 6.7L diesel can store it together with P20FA and P20FC, and the SSMs direct technicians to inspect connectors for moisture and corrosion. A pump that cannot be controlled ends DEF dosing until repaired.
- What you may notice
- Malfunction indicator lamp on
- DEF system warning, dosing suspended
- Countdown to restart lockout in the instrument cluster
- Likely causes
- LikelyPump B control line shorted to battery or supply voltage
- LikelyMoisture or corrosion bridging pins in the pump connectors
- RareInternal electrical fault in pump B
- RareFaulty output stage in the control module
- 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: €50 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.