Mazda 6 DPF problems (diesel particulate filter)

Mazda 6 DPF - diesel particulate filter



DPF stands for Diesel Particulate Filter and forms a part of the exhaust system.

The image above is a DPF from a Mazda 6.

The problem starts when soot accumulation rate in the DPF is 80 % or more, the DPF indicator light illuminates. In this case an automatic regeneration of the DPF must be performed by driving the vehicle at an engine speed of 2000 min-1 or more and a vehicle speed of 40 km/h or more for approx. 10…15 min. As soon as the automatic regeneration process starts, the DPF indicator light turns off.

NOTE: Although the DPF indicator light turns off when the automatic regeneration is started, the regeneration process is continued until the soot accumulation rate decreases to 60 % or less.

NOTE: If the customer complains that the DPF indicator light illuminates frequently, he must be informed to change the driving method (they should drive the vehicle at middle or high engine speeds for a longer distance), so that regeneration of the DPF is enabled.

If the soot accumulation rate in the DPF reaches 100 % or more, the DPF indicator light flashes and DTC P2458 is stored in the PCM. In addition, the PCM reduces the fuel injection amount to lower the exhaust gas temperature, preventing the filter from overheating. Due to the reduced injection amount the soot emission of the engine and hence the soot amount accumulated in the filter is also reduced. In this case a manual regeneration of the DPF must be performed.

NOTE: Do NOT perform automatic regeneration when the soot accumulation rate in the DPF is 100 % or more, since this may cause damage to the filter or the engine.

If the soot accumulation rate in the DPF reaches 140 % or more, the MIL (Malfunction Indicator Lamp) also illuminates and DTC P242F is stored in the PCM. In addition, the PCM (or ECU) further reduces the fuel injection amount and hence the soot emission of the engine, resulting in a lower soot amount accumulated in the filter. Here, a manual regeneration of the DPF must also be performed.

If the soot accumulation rate in the DPF reaches 200 %, the filter cannot be regenerated anymore and must therefore be replaced.

DPF regeneration table
Some customers use After Market DPF and find that after 6-9 months of having the After Market DPF fitted, they are having the same problems they had before. The After Market DPF is a cheaper way of solving a problem temporarily, also it is not platinum coated, does not come with the sensors and will get blocked very easily. So instead of having the After Market DPF fitted, why not solve your DPF problem and have a complete removal for lifetime peace of mind?