BMW 335D Xdrive Problems

Owners of the BMW 335d xDrive have reported issues related to the Diesel Particulate Filter (DPF). The symptoms range from warning lights indicating a blocked DPF to reduced power or even inability to drive. Given the high replacement cost of a new DPF, which can be around £2,400, many owners are keen to find alternative solutions and understand the underlying causes.

Forced Regeneration

One owner described a scenario where, after seeing a warning about a blocked DPF, they attempted a forced regeneration. This involves driving the car in a specific manner to get the DPF hot enough to burn off the accumulated soot. The procedure seemed to have worked, as indicated by the warning light going off and the tailpipes getting covered with black soot. This can be an indicator that the regeneration process took place and a significant amount of soot was cleared.

Possible Causes and Solutions

There’s speculation among some users that DPF issues might be related to the engine’s remapping, which modifies the car’s performance parameters. An increase in performance often involves higher fueling rates, which could potentially lead to faster DPF clogging.

However, other users have had remapped engines without encountering DPF problems. Factors such as the age of the car, driving habits, and even the condition of other components like the engine thermostat could play a role.

For those with tech inclinations, investing in a Wi-fi OBD2 adapter and software like Carly for BMW can be beneficial. This setup allows users to monitor the engine temperature, DPF status, and even trigger a manual DPF regeneration if needed. This proactive approach can help in addressing DPF issues before they become more severe.

Understanding DPF Regeneration

There’s a common misconception about the conditions under which DPF regeneration can occur. While some believe that high revs facilitate the process, in reality, several factors are at play:

• Sufficient fuel in the tank.
• Working glow plugs and their control relay.
• Engine temperature within specified parameters.
• Functioning pressure differential and temperature sensors.
• The DPF and catalytic converter reaching a certain temperature.
• Driving at a steady state for about 20 minutes at defined RPM.

Interrupting the regeneration process, like by stopping the car, can lead to incomplete regeneration. Advanced diagnostic tools can provide information about the last regeneration event by accessing the car’s ECU.

Need for Better Indicators

A suggestion made by some users is for manufacturers to introduce indicators that alert drivers when regeneration is taking place. Similar systems are already in place in larger vehicles, such as tractors. With such a system, drivers would be more informed and could potentially avoid actions that might disrupt the DPF regeneration process.

Conclusion

DPF issues in the BMW 335d xDrive can be frustrating, but understanding the underlying causes and potential solutions can help in managing the problem effectively. While remapping might be a contributing factor, several other aspects, including regular maintenance and driving habits, play crucial roles. Investing in diagnostic tools and staying informed about the car’s performance can significantly mitigate these issues.