DPF Maintenance

Diesel Particulate Filter (DPF) Maintenance

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Car Dealers! Discover why informing customers about Diesel Particulate Filter maintenance can improve your customer satisfaction ratings!

It’s time for some inside knowledge! Our Client Support Director Steve Robson has noticed concerns being raised by some of our Dealers relating to Diesel Particulate Filters (DPFs) on customer vehicles. I’m here to present his worthwhile advice in the hope of helping you and your customers!

DPFs are notoriously expensive. They are typically located close to the “engine end” of the exhaust system on most diesel vehicles. They are simply designed to trap soot emissions and help protect the environment, however, the filter can only hold so much before it clogs up.

The DPF sensors which are typically located either side of the filter itself, send data to the ECU. When the ECU senses a build-up of soot it starts a process called an “Active Regeneration Cycle” in an attempt to recharge the DPF by heating up the soot to 600 celsius. This turns the soot into a harmless ash which is then expelled via the exhaust tailpipe.

Herein lays the problem!

The ECU will only initiate Active Regeneration Cycle when the vehicle is being driven at an optimal running temperature, and cannot be initiated in low-speed urban driving conditions, especially when the engine coolant is cold.


Most customers are unaware of this,  so those that drive for prolonged periods at a low speed in stop-start, urban driving conditions, can unwittingly and prematurely clog up the DPF.


The first they usually know about it is when a dashboard warning lamp flashes on. If the driver ignores the light and if the ECU cannot initiate and complete the Active Regeneration Cycle, eventually the DPF will block.

The ECU will then force the vehicle into “Limp Mode” and the customer will end up at the workshop. In many cases, premature blockage of the DPF will require replacement at high cost.


It is only sensible that the customer is aware of how and why this happens. Customers can potentially avoid this issue by occasionally driving the vehicle on a long, clear stretch of road (as long as it is safe to do so), at a constant speed of at least 50 mph and at least 2,000 rpm for a minimum of 15 minutes.


Any interruptions in that 15 minute journey will not allow the Active Regeneration Cycle to recharge the DPF.

In Summary. By advising the customer at point of sale or vehicle handover about correct maintenance of the DPF, it could save you and the customer an awful lot in cost, time, effort, and stress minimise damage to your customer satisfaction rating.


Thank you for reading this WAS Blog post on DPF filter maintenance and awareness.