P2ACC
Reductant Temperature Sensor B Circuit
The ECM detects a generic fault on the reductant temperature B sensor circuit. Reading cannot be used reliably for control.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
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
Ordered by how often each turns out to be the cause.
- Sensor failedCommon
- Wiring or connector faultPossible
Parts involved
- Reductant Temperature Sensor B
- Wiring Harness
- ECM
P2ACC is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.