Powertrain
generic / SAE
P20AD
Reductant Metering Unit Temperature Sensor Circuit Range/Performance
Metering unit temperature sensor in range but fails plausibility — slow response or stuck reading. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / AD
Possible causes
- Sensor drift high
- Sensor element aged beyond calibration window low
- Sensor mounting loose - signal damping 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: hard
- DIY: shop recommended
- Estimated cost: 200–1500 €
- Estimated time: 1–4 h
- Component: reductant metering unit
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012