Thursday June 28 2018

Can a DPF light be repaired?


Hello Paul, my BMW 5 series E60 shows a DPF fault light. My mechanic says I have to buy a new one and it costs about Shs4m. Can the old one be repaired and why has mine failed? Isaac Bogere.

Hello Isaac, the DPF (Diesel Particulte Filter) fitted in some modern diesel vehicles is designed to trap exhaust particulate or soot and reduce environmentally harmful emission. The DPF system is designed to prevent damage from accumulation of trapped particulate ash by burning it. This process is called regeneration. It should happen when you drive constantly at speeds above 60kph for 15-20 minutes. DPF regeneration can only happen when you drive on a highway.

Regular or prolonged driving in urban traffic may prevent DPF regeneration. A blocked DPF will affect your car’s performance as the computer reduces engine power to prevent further damage. Signs of this are increased smoke and loss of power or a warning message on the dash board. The DPF can actively regenerate itself by running the engine at higher revs. Forceful regeneration can also happen at the garage using diagnostic tools with the DPF service platform.

There are special DPF service or cleaning kits which can be used to salvage or unblock the clogged DPF. A successful intervention will restore good engine performance. You can avoid DPF damage by fueling with cleaner diesel and servicing with recommended good quality engine oil both of which reduce harmful exhaust emission.