OBD-II code · Powertrain (generic, extended)
P2ACF Reductant Temperature Sensor B Circuit High
Voltage on the reductant temperature B sensor signal line is above the expected window. Wire shorted to B+ or sensor open.
Is it safe to drive with P2ACF?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelySignal wire shorted to B+
- PossibleOpen sensor
- Less likelyConnector pins corroded - high contact resistance
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)
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.5 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Temperature Sensor B, Wiring Harness, Ecm
Related codes
- P2045Reductant Temperature Sensor A Circuit High
- P2ACCReductant Temperature Sensor B Circuit
- P2ACDReductant Temperature Sensor B Range/Performance
- P2ACEReductant Temperature Sensor B Circuit Low
- P2AD0Reductant Temperature Sensor B Circuit Intermittent/Erratic
- P2AD1Throttle/Pedal Position Sensor/Switch C/G Voltage Correlation
- P2AD2Throttle/Pedal Position Sensor/Switch B/G Voltage Correlation
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.