Powertrain
generic / SAE
P204B
Reductant Pressure Sensor Circuit Range/Performance
DEF pressure sensor reads within electrical range but plausibility fails — does not rise during prime, drift over a drive cycle, or stuck at a constant value.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / 4B
Possible causes
- Sensor drift or stuck reading high
- Pump pressure builds slowly medium
- Sensor element aged beyond calibration window 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: 100–800 €
- Estimated time: 0.7–3 h
- Component: reductant pressure sensor
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012