OBD-II code · Powertrain (generic, extended)
P24D3 Reductant Heater B Sense Circuit
Reductant Heater B Sense Circuit: an electrical fault is present in the circuit. The reductant (DEF/AdBlue) heater keeps the urea fluid from freezing; a fault can impair SCR dosing in cold conditions.
Is it safe to drive with P24D3?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen in sense wiring
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
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–3 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Heater B
Related codes
- P24D2Reductant Heater A Sense Circuit
- P24D0Particulate Matter Sensor Supply Voltage Circuit Low
- P24D1Particulate Matter Sensor Regeneration Incomplete
- P24D4EGR Cooler Coolant Pump Feedback Circuit
- P24D5EVAP System Pressure Sensor or Switch B Circuit
- P24D6EVAP System Pressure Sensor or Switch B Circuit Range or Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.