OBD-II code · Powertrain (generic, extended)
P24FF Reductant Temperature Too High
The temperature of the AdBlue/DEF in the dosing system exceeds the safe limit — risk of thermal decomposition (NH3/biuret formation) and clogged dosing nozzles. Often caused by a stuck-on tank heater, a stalled coolant return or proximity to a hot exhaust component.
Is it safe to drive with P24FF?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyTank heater stuck on
- PossibleHeat soak from exhaust or engine bay
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
- 0.6–3 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Tank, Reductant Tank Heater, Reductant Lines
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.