The DPF (Diesel Particulate Filter) is an Anti-Pollution/emissions reducing device. It is designed to reduce the number of emissions your car produces by capturing a portion of the soot and other non-combustible materials within the DPF cannister.

The exhaust gases and are forced through the filter and the soot deposits on the inner walls. The amount of soot captured is measured by the DPF Differential Pressure Sensor. When the DPF becomes full, the vehicles ECU recognises that the deposited soot collected now needs to be burned.

The process of burning the soot is called DPF regeneration, the ECU will control the function to provide post combustion fuel injection to allow the heat of the of the exhaust fumes to rise to a temperature over 600°C, it can then burn the deposited soot. This is referred to as ACTIVE DPF REGENERATION. 

 

 

 

 

 

 

 

 

After your vehicle has travelled a number of miles or over period of time the residual non-combustible contents will eventually block the DPF.  When a DPF becomes blocked the ECU will not be able to engage the DPF Regeneration function and your vehicle may experience a loss of power and illuminated Engine Management Lights (EML). This Restricted power safety mode is referred to in the motor trade as “limp mode”.

Typically, the service life cycle of a DPF is around 120,000-150,000 miles, this can vary dependant on the make/model and how many short journeys the vehicle undertakes.

 

 

 

 

 

 

 

 

If a DPF has become blocked before its service life cycle is due to end naturally, then this is an indication that there is a fault upstream of the DPF. It is imperative that the fault that caused your DPF to block is fixed at the same time as having your DPF repaired or replaced. Without addressing the root cause, your new/repaired DPF will also become blocked far quicker and potentially cause further mechanical faults.

Vehicles that do not undertake any long journeys will suffer with DPF issues more frequently. This is because not enough time has been spent in the vehicle to engage the DPF Regeneration function and therefore these DPF`s become blocked far quicker.

Vehicles will burn soot naturally when the vehicle is being run at steady high speeds for long durations, this is because exhaust fumes are far higher in temperature allowing more of the soot to burn and this is called PASSIVE DPF REGENERATION.

A DPF is fitted with Multiple Sensors which are prone to failure, please see below:

• Oxygen & NOx Sensors – These monitor the concentration of oxygen & Nitrogen Oxides in the exhaust gases
• Differential Pressure Sensor – These measure back pressure before and after the DPF and determines the percentage of soot contained within the DPF.
• Exhaust Gas Temperature (EGT) Sensors – These are electronic probes used to measures the temperature in the exhaust before and after the DPF

Differential Pressure Sensor

 

 

 

 

 

 

 

 

Oxygen Sensor

 

 

 

 

 

 

 

 

Exhaust Gas Temperature (EGT) Sensor 

 

 

 

 

 

 

 

 

If the DPF Sensors fail this could ultimately prevent your vehicle from engaging the regeneration cycle or provide incorrect feedback to the ECU causing issues with fuelling. If your vehicle sends incorrect quantities of fuel to the injectors this may not be able to be burned and therefore leaves far higher soot deposits in the DPF.

If the EGT sensors fail, your vehicle will not be able to monitor the temperature in the exhaust and therefore the ECU will prevent the regeneration cycle starting again.  

The Exhaust Gas Recirculation (EGR) valve are prone to develop faults, this can also impact the amount of soot deposited in the DPF. This happens when valve is slow to respond, fails or sticks. This can create a leak under boost conditions and result in higher soot contents depositing in the DPF and potential performance issues.  

Faulty Fuel Injectors can be the root cause of some DPF problems. Injectors that are worn or have become faulty will cause poor fuel atomisation leading to poor combustion, excessive soot, and more particulate matter.

Where an engine or a turbo have become, faulty this will lead to excessive oil being burned. If there is excessive oil being burned during driving this will lead to excessive matter for the DPF to burn and will increase the need to regenerate the DPF.

Our advice is to allow your vehicle to complete a 20+ minute passive burn cycle once a week. To allow the exhaust temperature to rise the specified heat to burn the DPF soot content we recommend you keep the revs above 3000 rpm.

Using good fuel will create less soot waste/emissions and burn cleaner for the environment. Regular servicing of the engine oil using the correct manufacturer specification will also help to prevent particles from the oil blocking the DPF**.  

Make sure any Adblu or SCR tanks are kept topped up.  

**Oil Quality – high ash content oil produces silica particles which are unable to be burned by the DPF.

Click here to book your vehicle in for a service

Our team of technicians are equipped with dealer level tools and are all highly trained in DPF diagnostics.

 

 

 

 

 

 

Where your vehicle has engaged its safety restricted mode (limp mode) to protect itself due to a DPF fault, our technicians are able to give you an honest opinion on your DPF’s health by checking the following:

• Are there any fault codes affecting the operation of the DPF
• Can the vehicle still be safely regenerated using diagnostics equipment
• What is the soot content / soot accumulation in the DPF
• Is the DPF blocked completely and no longer able to function

On some occasions a vehicle will stop the process of regenerating the DPF normally through driving. In safe conditions our diagnostic tools can force the vehicle to regenerate the DPF and return the vehicle to its normal functions.

On some vehicles our advanced diagnostics tools can check the actual soot content / soot accumulation to see what percentage of the DPF is full. This will give an indication of how much life is left in the DPF.

 

 

 

 

 

 

 

 

If the DPF is completely blocked and beyond repair our technicians will provide a comprehensive report and offer a range of solutions.  

Many garages miss the root cause of why a DPF has become faulty, in many cases the reason the DPF has become full quicker than normal is due to faults in other areas of the vehicles running gear.

Common DPF related faults:

• DPF is blocked / compacted with fine soot.
• DPF Pressure Sensors have failed preventing DPF regeneration.
• leaking injectors, valve stem oil seals, worn piston rings.
• Poorly calibrated Software / performance tuning.
• Adblu faults
• EGR Faults

 

 

 

 

 

 

 

Many vehicle owners are unaware that the Adblu function on their vehicle is connected to the functionality of the DPF. Diesel Vehicles that are complaint with the Euro 6 standard use the Adblu system to reduce the vehicles emissions.

Adblu is a liquid mixture of Urea and Deionized water, this liquid is sprayed into the exhaust to help the burn process of the exhaust fumes to lower the emissions produced by the vehicle.

 

 

 

 

 

 

 

 

When your Adblu system is running low, it should notify you on the dash message screen (Show pic of Adblu ticker). If the Adblu runs out of liquid this can immobilise some vehicles, it is therefore advisable to keep your Adblu tank topped up. You can buy Adblu from most fuel stations and some supermarkets.

 

 

 

 

 

 

 

 

Sometimes the Adblu system can fail and impact the DPF function. Our expert team of technicians are experienced in using advanced diagnostics to pinpoint faults relating to the Adblu and DPF systems in your vehicle.

For more information on Adblu please click the link to our information post.

If you are experiencing problems with your Adblu please drop one the team a message

There are lots of companies offering DPF cleaning services, where they will physically remove and wash the DPF using pressurised water and chemicals.

The DPF honeycomb structured ceramic material is laden with chemicals and platinum. It is designed with these materials so it can withstand the heat of the fumes and regenerate the DPF efficiently.

Our opinion on this method of cleaning the DPF is:

The DPF was never designed to be a serviceable item on your vehicle, and they have a life cycle.

Once these chemicals and materials have been flushed the vehicle will potentially see some temporary benefit however, in the long term we have seen the damage such methods cause. Using additives, flammable liquids eventually damage the integrity of the DPF’s honeycomb structure.

 

 

 

 

 

 

 

 

Often these companies are not qualified or experienced in diagnosing other mechanical issues which may have led to your DPF failing.

Our advice would be to stay away from carbon cleaning flash and dash companies offering services that will cause more damage.

If your vehicle is experiencing DPF issues or you have warning lights on your dash and your DPF is blocked no longer functioning: Please call to make a booking for DPF Diagnostics

If your vehicles DPF is past the point of repair and is no longer functioning, we can offer you our replacement fitting service. We supply our parts direct from the manufacturer, so your vehicle does not have any performance issues. Many aftermarket products are available however the quality and longevity of these parts often falls short of the performance required for your vehicle.

If you have bought a vehicle that has had the DPF removed prior to purchase and you are looking to have a new DPF fitted, we can offer you our replacement fitting service and software to return the vehicle back to the original manufacturer specification.

We offer competitive pricing for fitting on DPF replacements, our team of technicians will have your vehicle fault free and back to its original performance.

Click here to book your vehicle in for our DPF Replacement Service (Finance Available)