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Diesel Particular Filter (DPF)

Applicable Diesel Models Only

Most diesel vehicles have been designed to meet the latest environmental regulations concerned with exhaust gas emissions.

In order to limit the amount of small soot particles contained within the diesel exhaust gas passing into the atmosphere,this vehicle has been equipped with a diesel particulate filter (DPF). This filter forms part of the vehicle's exhaust system and is similar in construction to a catalytic converter. It traps and stores solid particles or ‘soot', produced by diesel engine combustion, in a honeycomb matrix made of a ceramic material.

When the amount of soot in the filter reaches a specified level, this needs to be reduced to maintain the filter's function. This reduction of the particulate matter is called regeneration and must be performed periodically. A DPF can remain effective for a long service life through repeated cycles of trapping particulate matter and regeneration.

Usually this regeneration is carried out by the vehicle's electronic control systems raising the exhaust gas temperature, during normal driving, without the driver being aware.

If however the vehicle is only driven either on short journeys, or at low speed, then it may not be possible for the exhaust gas to reach a high enough temperature for regeneration. In this situation, the DPF warning light on the dashboard will be illuminated.

As soon as possible after the DPF warning lamp illuminates, you should drive the vehicle at a speed above 40 mph until the light goes out. Depending on the amount of accumulated soot this can take up to 30 minutes. It is important that this is done at the earliest opportunity.

Always drive the vehicle in a safe manner according to traffic conditions and obey traffic laws when driving.

If, after the DPF warning lamp illuminates, the vehicle continues to be driven in a style whereby the exhaust gas temperature cannot be raised sufficiently, then the vehicle's electronic control system performs the following actions to protect the DPF and the engine:

  • The engine warning is illuminated together with the DPF warning lamp.
  • The vehicle may enter "fail-safe" mode and limit engine speed to a maximum of 3,000rpm.

To recover from the condition described above, SERVICE REGENERATION of the DPF is required. This can only be carried out by a workshop equipped with diagnostic equipment. In addition, whenever SERVICE REGENERATION has been carried out, the engine oil and filter must be replaced.

IMPORTANT: To avoid the need for SERVICE REGENERATION it is very important to drive the vehicle at higher speeds as soon as is practical after the DPF warning light illuminates. Once the engine warning lamp is illuminated, driving at higher speeds will not regenerate the DPF.

If SERVICE REGENERATION is required it is not a fault with the vehicle and will not therefore be covered under warranty.

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