Powertrain, generic (extended)

P208B Reductant Pump A Control Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P208B is the functional check of DEF pump A: the circuit is intact, yet the pump ignores its command or stays off. Ford, titling it Reductant Pump Control Range/Performance, sets it on 2023 diesels when pump speed misses its setpoint by over 300 rpm or its speed control sits at a limit for 30 s, detected within 5 s and only after the circuit tests have passed. GM's 2014 diesel table reports Reductant Pump Performance when the pump motor's functional acknowledgement takes longer than 4 s, Type B. Deutz EMR5 adds an overheated output stage (P208B-4B) and an abnormal rate of change (P208B-92). In the field the hydraulics are usually to blame: FCA STAR S1925000008 (Grand Cherokee, Wrangler diesel) names trapped air in the tank filter and external leaks, and a Volkswagen 2.0 TDI tip rules out leaking lines first.

Likely causes

Air trapped in the tank filter or suction side after service
Leaking DEF line or connection between pump and dosing valve
Worn, frozen or crystallised pump
Calibration needing an update (FCA 3.0L diesel)

Symptoms

  • MIL with DEF system message, often with P20E8
  • White urea crust on lines or fittings
  • Countdown to no-restart or reduced power

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–1,800
Time0.5–4 h

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

Parts involved

reductant pump

Related codes

P208AP208CP208DP201FP20E8P20FB

References: fordservicecontent.com, gsi.ext.gm.com, serdia.deutz.com, static.nhtsa.gov.