Powertrain
generic / SAE
P20FA
Reductant Pump B Control Circuit/Open
The control line driving DEF pump B is open. On large engines or dual-tank systems a second pump (B) supplements pump A; with B offline the system loses redundancy.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / FA
Possible causes
- Pump motor winding open high
- Pin pushed back out of connector body low
- Cracked solder joint inside the module or sensor low
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 150–1100 €
- Estimated time: 1–3.5 h
- Component: reductant pump
- Component: reductant pump relay
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012