Powertrain, generic (extended)

P20FC Reductant Pump B Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P20FC sets when the drive signal for reductant pump B reads too low, typically a ground fault on the line or a current draw beyond what the driver allows. Pump B has no published limits. For pump A, Ford's 2023 diesel summary reports the low fault (P208C) when pump current exceeds 5 A or the pump controller draws more than 15 A, checked with the driver off and confirmed after about 8 seconds; a similar logic is likely for pump B but undocumented. The only codegenau manufacturer evidence comes from Ford: 2023–2024 Super Duty and F-650/F-750 6.7L trucks may log P20FC alongside P20FA and P20FD, and the SSMs point to wet or corroded connectors first. Unlike P20FA, the circuit is not open but pulled down; unlike P20FD it is not stuck high.

Likely causes

Chafed wire shorting the pump B control line to ground
Water ingress or corrosion in the pump connectors
Pump B motor drawing excessive current (internal short or tight motor)
Faulty output stage in the control module

Symptoms

  • Malfunction indicator lamp on
  • DEF system warning and reduced or no reductant dosing
  • Restart lockout after the inducement countdown if left unrepaired

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–900
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

reductant pumpwiring harness

Related codes

P20FAP20FBP20FDP208C

References: static.nhtsa.gov, static.nhtsa.gov, fordservicecontent.com, law.cornell.edu.