Investigate soonamber light
DPF (Diesel Particulate Filter)
Soot filter is clogging — take it for a steady motorway run.
What it means
An amber rectangle with dots above it, representing the filter and trapped soot. The Diesel Particulate Filter is full of soot and needs to ‘regenerate’ — burn it off — which requires sustained high exhaust temperatures. Lots of short urban journeys can prevent this from happening.
What to do
- 1Take the car for a 20–30 minute drive on a motorway or A-road at 50–70 mph in a lower gear (around 2,500–3,000 rpm).
- 2The light should go out as the regeneration completes.
- 3If it doesn’t clear, or a red light appears, get it diagnosed — forced regeneration or replacement may be needed.
- 4Never ignore it — a fully blocked DPF can cost £1,000–£3,000 to replace.
Likely causes
- •Lots of short, low-speed journeys (school runs, city driving)
- •Faulty differential pressure sensor
- •Oil dilution from incomplete regenerations
- •Underlying engine fault adding extra soot
Rough UK cost
Forced regen at a garage: £100–£250. DPF clean: £300–£600. Replacement: £1,000–£3,000.
Prices are a guide only — always get a written quote before any work.
Heads up: Carautonomy is for general guidance only. If your car is behaving oddly or any red light is on, get it inspected by a qualified mechanic.