Powertrain
Definition only
Lights the check engine lamp
P208B: Reductant Pump A Control Performance/Stuck Off
Standardized SAE J2012 code · P20xx — Fuel & air metering and auxiliary emission controls
What does P208B mean?
DEF pump A receives a run command but does not start, or shuts off prematurely — pump performance is below threshold.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
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)
Common causes
- High Pump motor seized — DEF crystallised inside pump head
- Medium Motor brushes worn
- Low Carbon or debris buildup preventing free movement
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P208B on the same make and model first.
P208B in the community
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