Exhaust filters are also known as particulate filters. Vehicles fitted with these filters have more efficient emissions control. The particles in the exhaust gases are collected in the exhaust filter during normal driving.
Cleaning of the exhaust filter is also known as regeneration. Regeneration occurs automatically depending on driving conditions. Self-cleaning only occurs when the engine has reached its normal operating temperature.
Self-cleaning takes place while driving, although the characteristics are different for diesel and petrol engine vehicles.
Self-cleaning takes place when the vehicle is driven steadily at speeds between 60 km/h and 112 km/h (37 mph and 70 mph). The process normally takes 10 to 20 minutes. Self-cleaning can occur at lower vehicle speeds, but the process may take a little longer at a 50 km/h (30 mph) average speed.
Some driving conditions may not provide sufficient opportunity to begin the exhaust filter self-cleaning automatically. For example: frequently driving short distances in slow-moving traffic, or cold weather. If automatic self-cleaning is not possible, the instrument panel displays a series of messages.
A small increase in fuel consumption may be noticed temporarily during exhaust filter self-cleaning.
If diesel fuel with high sulphur content is used regularly, the exhaust may emit a cloud of smoke at the start of the self-cleaning process. The smoke is a result of the sulphur deposit being burnt off and is no cause for concern. If possible, only use low sulphur diesel fuel.
Self-cleaning takes place when the engine is at its normal operating temperature and sufficient oxygen is present in the exhaust stream. In most situations, the exhaust filter automatically self-cleans without any driver intervention necessary.
Some driving conditions, e.g., repetitive cold starts or continuous full-load driving, may not provide sufficient opportunity to begin the exhaust filter self-cleaning automatically. If automatic self-cleaning is not possible, the instrument panel displays a series of messages.
If a restricted performance message is displayed, contact a retailer/authorised repairer as soon as possible.
An increase in the idle speed may be noticed temporarily during exhaust filter self-cleaning.