The DPF warning light is an indicator on a vehicle’s dashboard that informs the driver that there is an issue with the diesel particulate (DPF) system or emissions system.
There are variations in the way the light presents itself that indicate different actions being required.
The light won’t turn off
If your DPF warning light is on ‘solid’, meaning it is remaining on and not flashing or switching on and off, it’s likely time to hit the road.
This persistent light can indicate the vehicle is being driven in short distances and an active regeneration has been unable to be performed or completed during day-to-day driving. We recommend checking the owner’s manual of your diesel vehicle to understand the optimal driving style for your car.
General advice would be to go for a drive upwards of 30 minutes, preferably on a highway or open road where minimal stop-starts can occur, to enable an active regeneration.
The light is flashing
A flashing DPF warning light can have two causes:
- DPF fill level is over-capacity and needs to be removed or replaced.
An over-full fill level, can be caused by: an upstream issue (i.e. relating to injectors, EGR or the boost-leak system); driver error (i.e. not meeting manufacturer requirements for driving cycles); or a faulty sensor. A likely cause may also be that there is too much ash accumulation in the DPF from being on the vehicle for an extended period and needs to be removed for cleaning.
- The vehicle oil level is too high.
This needs to be confirmed by a mechanic, who will be able to check the oil dilution ratio via a scan tool. If the scan tool indicates the ratio is above threshold, an accompanying symptom will be that the actual oil in the vehicle will appear to have been overfilled. This is likely not the case, rather, the oil dilution may not have been reset during previous service or there could be a more complex matter at hand with the DPF system which is causing frequent regeneration attempts, subsequently causing the oil level to rise.
How do you clear the DPF warning light?
When your DPF warning light appears, it’s important to contact your local mechanic as soon as possible. A qualified automotive mechanic will be able to perform a root cause analysis and determine the best next steps for your specific vehicle and circumstances.
Post repair, clean or regeneration, your mechanic will be able to use a scan tool to clear the DPF light.