This vehicle comes fitted with a system that filters the exhaust air to limit the amount of carbon soot that enters the atmosphere. The system is called Diesel Particle Filter (DPF) and it has been implemented by Mazda on all its diesel engines. The Mazda cX5 DPF problem may arise due to a number of factors that will be discussed in this article but first let’s outline the indication of the problems. 

Signs of  Dpf problem 

Check Engine Light /DPF Warning Light  

These lights will illuminate on the cluster instrument   accompanied with the following DPF related faults when you connect your diagnostic tool: 

• P2002 – DPF efficiency below threshold (Bank 2) 
• P242F – DPF restriction – Ash accumulation 
• P2458 – DPF regeneration duration 

• P2459 – DPF regeneration frequency 
• P2463 – DPF Restriction – Soot accumulation 
• P244A – DPF Pressure too low (Bank 1) 

High fuel consumption + Low  performance 

When the Mazda CX5 DPF is blocked,  it will over fuel to increase the exhaust temperatures that burn the soot particles. It cannot effectively use the extra fuel, hence the vehicle enters into “restrictive performance” mode to prevent further damage. 

White smoke 

The vehicle will occasionally let out white soot when idling. This usually happens when the DPF has been breached or tampered with as this video shows.

Cause of Dpf problem  

Factors causing these emission systems to fail include bad driving habits, poor-quality fuel, and falling air/ fuel mixture in the engine during combustion. For instance, continued short-distance driving is considered a bad driving habit for the Mazda cX5 Dpf. This pattern of driving is unsuitable for the Dpf to self-clean as the exhaust temperatures are not high enough to burn the soot particles. A change in driving habits may help if it was the root cause. 

The quality of fuel is one of the major factors in the functionality of the diesel particulate filter. This means that the use of high-quality fuel will prolong the useful life of the Dpf system.  Fuel shortages result in hoarding and subsequent storage of diesel in substandard and often contaminated containers. Developing countries experience this problem more than developed ones. DPF problems, therefore, arise as a result of contaminated diesel combustion. 

Leaking air intake leads to the production of excess carbons that will cause the Dpf to clog quickly. It causes soot accumulation to occur at a faster rate thereby overwhelming the self-cleaning system. To avoid leaks regular checks of the air to fuel mixture ratios is essential.

The Fix

There are several courses of action that can be taken to solve the Mazda CX5 DPF  problem. Consider each solution so that an informed decision can be made. 

1) Regeneration  

This process requires initiation by an advanced diagnostic tool. Once initiated the exhaust temperatures will rise extremely high in order to burn the soot particles clogging the DPF. This solution can last weeks, days, or just hours and sometimes it might not even work. If it works then an investigation of the DPF problems has to be conducted so that the causes can be dealt with to prevent a recurrence. Sadly, in some instances, forced regeneration does not complete successfully and other solutions have to be considered.  

2) Replacement 

 You may have looked up the cost of buying a brand new DPF and yes, it’s extremely expensive. Before you buy consider watching this video so you can make an informed decision. Usually, if a car gives you DPF problems once and you buy a new DPF the likelihood of those problems resurface is 90%. DPFs are meant to last the lifetime of the vehicle and if that is not happening it means there is an underlying issue. In essence, if the factors that lead to the clogging of the DPF are not fully discovered and addressed then if you buy new DPF this will likely be a complete waste of money. 

3) Emulators 

 This is another solution available where you buy a device that will emulate a good working DPF. At our workshop, we have seen vehicles with emulators. These are very dangerous as they mimic and falsify signals to the ECU. The danger lies in that most of these emulators are untested.  We have seen damaged ECUs and engines due to inconsistent signals brought by emulators. The result is usually a malfunctioning ECU that ends up destroying the engine or hindering its optimum performance. Based on what we have seen we would not encourage this route at all.

4) Conversion to Non-DPF 

Conversion to non DPF also known as DPF delete is a more permanent solution that may come with profound benefits to your vehicle if done well. This entails modifying both the hardware and software of the system. The DPF Team highly recommends that you check with the laws if these modifications are permitted as some countries make this illegal to do. The Engine Check light will disappear, power will actually increase and fuel consumption will improve as soon as the conversion is completed. When we implement this at our workshop it comes with lifetime guarantee. Here is a documentary of us performing that service for our customers with dyno tests of before and after results: