Diesel Particulate Filter Light

What it means

The diesel particulate filter in the exhaust is filling with soot and needs a self cleaning burn off, known as regeneration. It commonly happens on cars used for short city trips where exhaust temperature never gets high enough.

Symptoms5

• A steady amber light.
• Reduced power or the car entering limp mode.
• Higher fuel consumption.
• A burning smell from the exhaust.
• The radiator fan running after the engine is switched off.

Possible causes5

• Frequent short trips at low speed.
• Regeneration interrupted by switching the engine off.
• A faulty differential pressure sensor on the filter.
• Engine oil not suited to modern diesel engines.
• Weak diesel injectors producing extra smoke.

How to diagnose and fix6

1. Drive on a highway at a steady moderate speed for 15 to 20 minutes to allow regeneration.
2. Do not switch off the engine during regeneration if a message indicates it is running.
3. If the light stays on, have a workshop run a forced regeneration with a scan tool.
4. Check the differential pressure sensor and its hoses.
5. Use oil that meets the manufacturer specification.
6. In advanced cases the filter may need off car cleaning or replacement.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

A highway drive costs nothing, a forced regeneration is moderate, and a new filter is very expensive.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.

Frequently asked questions