During an active filter regeneration the controller is meant to steer the temperature ahead of the particulate filter with feedback from the exhaust temperature sensors, usually by adjusting late fuel injection or a hydrocarbon dosing valve in the exhaust. P249F is stored when the regeneration spent too little of its duration in that feedback mode. Ford's 2023 diesel summary judges the closed-loop share against a threshold that depends on total regeneration time, checked once per regeneration at 1000 to 3500 rpm. Volvo truck bulletin K86412082 (model years 2016 to 2018) pairs P249F with P24A0 on engines with a seventh, aftertreatment hydrocarbon injector and points first to engine and aftertreatment software. P24A0 and P24A1 cover a loop that runs but saturates. The driver normally notices only the lamp.
Medium severity. Can I keep driving?If the light is on steadily, take a highway drive or go to a repair shop soon. If the car is in limp mode or the light is flashing, do not push the engine.
Symptoms
- Malfunction indicator lamp on
- Regeneration may take longer or repeat more often
- Often no change in driveability
Most likely causes
- Engine or aftertreatment module software needing an update
- Exhaust temperature sensor ahead of the oxidation catalyst or filter reading wrongly
- Hydrocarbon dosing valve in the exhaust restricted or slow to respond
- Regenerations repeatedly interrupted by short trips or changing load
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It affects emissions.
What each character of P249F means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 4: Emissions
- 9F: Specific fault in that system
Frequently asked questions
Can I keep driving with code P249F?
If the light is on steadily, take a highway drive or go to a repair shop soon. If the car is in limp mode or the light is flashing, do not push the engine.
What causes code P249F?
The most common causes are: engine or aftertreatment module software needing an update; exhaust temperature sensor ahead of the oxidation catalyst or filter reading wrongly; hydrocarbon dosing valve in the exhaust restricted or slow to respond.
Related codes
- P24A0Closed Loop Particulate Filter Regeneration Control At Limit - Temperature Too Low
- P24A1Closed Loop Particulate Filter Regeneration Control At Limit - Temperature Too High
- P244CExhaust Temperature Too Low For Particulate Filter Regeneration (Bank 1)
- P244DExhaust Temperature Too High For Particulate Filter Regeneration (Bank 1)
Sources
- fordservicecontent.com: obd summary diesel 2023
- static.nhtsa.gov: MC 10129129 9999
- law.cornell.edu: 13 CCR 1968.2
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.