Symptoms
- DPF icon (often a filter with dots) lit on the dash
- Possible reduced power or rougher idle
- May notice more frequent regeneration cycles or a hot exhaust smell
Likely causes
- CommonFilter needs a regeneration cycleShort, low-speed trips don't get the exhaust hot enough to burn off soot naturally.
- CommonFailed or incomplete regenerationInterrupting a regen cycle partway through can leave the filter partially clogged.
- PossibleFaulty pressure or temperature sensor on the DPFSends incorrect data about filter soot levels.
- PossibleFilter significantly clogged from years of short tripsMay need a forced regeneration or professional cleaning.
- Less commonRelated engine or fuel system issueUnderlying issues like injector problems can prevent proper regeneration.
What to do
- Check your owner's manual for how to trigger or support a regeneration cycle for your model.
- If possible, drive on the highway at a steady, higher speed for 15–20 minutes, which often completes a regen automatically.
- Avoid short stop-and-go trips until the light clears, since these prevent regeneration.
- If the light flashes or is joined by reduced power, avoid highway speeds and have it checked instead.
- Have a shop run a forced regeneration with a diagnostic tool if driving doesn't clear it.
- Get the pressure/temperature sensors checked if regeneration attempts consistently fail.
- Have the filter professionally cleaned or replaced if it's too clogged to regenerate.
When to call a pro
See a diesel specialist if highway driving doesn't clear the light, or if it flashes along with reduced power.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.