Category Archives: Diesel Particulate Filter (DPF)

Spareco Case Study Report: 17-6-14

Spareco Case Study Report: 17-6-14

The following report aims to establish the facts in relation to warranty claims on an aftermarket Diesel Particulate Filters (DPF), Part No. DPF003SC, supplied by (information redacted) to Mazda in (redacted) in April 2014, the vehicle and specified issues are outlined separately with their issues and suspected causes outlined in black text and the recommended course of action Spareco believes should have been performed at the time outlined in red text.

MAZDA 3 ((redacted) DEALER)

Car Details as given by (redacted) Mazda / (redacted): Mazda 3 2.0L Turbo Diesel

This vehicle was bought by (redacted) Mazda as a used car and was found to have a failed Diesel Particulate Filter. After attempting to clean the unit with degreaser and a pressure hose several times and refitting it to the car to obtain a forced regen, it was found that the “front of the DPF had melted”. (redacted) Mazda had not seen this vehicle before and had no service history on the vehicle.

Process recommendation:

• The history on this vehicle should have been checked for evidence of a reason for initial failure.

• The pressure/temperature sensors should have been checked before replacement of DPF.

When it was discovered that the original unit had melted down this should have raised flags for the dealer alerting them to an underlining issue.

• Further diagnosis and pre checks as outlined in DPF Fitment Guide for the Professional should have been completed before the DPF unit was replaced.

At this point a new silicone carbide unit was sourced by the Sales Department at (redacted) Mazda; it was purchased though the Parts Department and supplied to the Service Department for fitment.

“There were no fitting instructions attached to the unit just a part number and the contact details for (redacted) was the only things attached. We spoke to (redacted) about fitting and there was no mention about special circumstances around the DPF or things we should check”

The unit was fitted by Service, the oil and filter were changed, Engine Management Unit values were reset and there was a forced regen completed on the new Diesel Particulate filter without issue as per the Mazda replacement schedule. Both Sales and the Service Department test drove the vehicle with a combined distance of approximately 100km before the vehicle was put on a truck and taken to (redacted) Mazda for sale.

Process recommendation:

• There should have been attached to this unit the Warranty label as well as a copy of the DPF Fitment Guide for the Professional.

• When (redacted) Mazda spoke to (redacted) more info was required about correct fitting process including pre-checks and fitting guide should have been supplied.

MAZDA 3 ((redacted) DEALER)

Car Details as given by (redacted) Mazda / (redacted): Mazda 3 2.0L Turbo Diesel

While on test drive with a possible customer the vehicle was reported to lack power and during the test drive entered the Limp Mode bringing on the engine light. It was given to (redacted) Mazda Service Department for diagnosis and after some investigation it was found that the DPF was causing a restriction in power as well as having a higher than recommended pressure differential. A forced regen was performed however on road test the same issues were felt with restricted power and eventually the Limp Mode occurred again. The unit was removed as well as the injectors and inlet manifold for check and further diagnosis.

The injectors were checked by a local independent (redacted) Diesel Services and the following results were found.

1. Injector 1 was found to pass all tests (both return and delivery) with notes stating only a slightly higher than average specification fuel return.

2. Injector 2 was found to be the same as Injector 1

3. Injector 3 was found to have excessive return. Over a 1 minute return test with a maximum return of 30cc allowable an amount of 500cc approximately (the test was withdrawn at 30 seconds due to results) was found. A delivery test was not completed due to overwhelming return issue.

4. Injector 4 was found to have an acceptable return however its delivery was found to be only 59mm³ where a specification of 70mm³ is needed.

5. These tests were completed by a trained technician on a Bosch EPS200 series test bench using a Redat equipment update. (Denso Injectors).

All 4 injectors have since been replaced and the Engine Management System has been recoded to work with these calibrated injectors. Both the intake manifold and EGR were also removed however there were no reported issues with either. It should be noted that inlet manifold blockage is a common occurrence in these vehicles and that it can be extremely detrimental to the service life of a Diesel Particulate Filter.

The DPF was replaced with one borrowed from another used car and has since had no further issues with approximately 150km travelled.

Process recommendation:

• The history on this vehicle should have been checked for evidence of a reason for initial failure.

• These issues should have been picked up by the (redacted) Mazda Dealer as part of there pre-replacement process as outlined in the DPF Fitment Guide for the Professional


It is the opinion of Spareco that this vehicle was not diagnosed correctly in accordance with best practice DPF diagnosis and replacement. The following points summarise our thinking

1. The cars history was not sufficiently checked.

2. All recommended vehicle technical checks were not carried out.

3. Recommended DPF replacement process was not followed.

Other important notes:

• A new fitting kit should have been used.

• Engine sealant should not have been used to seal either end of the replacement DPF unit. (There was evidence of silicone sealant upstream of the particulate filter.)

• There are no recorded pressure differential readings from either Mazda Dealer even after failing 2 separate Diesel Particulate Filter’s. (OE and Zetti Emissions product)


Overview of Objectives:

A sample of ash has been supplied to an independent test facility for analysis to further understand the cause of failure in the supplied Diesel Particulate Filter DPF003SC, supplied by (information redacted) to Mazda in (redacted) in April 2014. See Picture 1 & 2 below.


Picture 1



Picture 2



Picture 3


Ash Test Results:

Understanding of the Test Graph (Refer Picture 3)

To understand the graph shown, the X line is Time, the Y-1 line is Weight and the Y-2 line is Temperature.

The test we perform consists of 77 minutes of increasing the temperature (Y-2 Blue) from room temperature to 400 degree’s. We then maintain a 400 degree temperature for 30 minute’s during this
time any raw diesel / oil contamination within the soot will burn off. Looking at the Green Y-1 line it starts from 100%, this will always start from 100% as the soot loaded equals this figure. This value
can only decrease as the test continues as the soot, raw diesel / oil is burning and decreasing the overall weight. The point stated on the green line is the final per-cent after the 30 minutes of 400 degree burn time, the per-cent shown at this point is the per-cent of soot left after the 400 degree burn time of 30 minutes. As stated previously any oil or raw diesel contamination within the soot will have burn off during this time. For example – the point shown on the graph states : 92.00 %, this means at a temperature of 400 degrees after 30 minutes the soot content now is 91.66 % from 100 % from the beginning of the test, so 100% – 91.66 % = 8.34 % , this 8.34% is burnt oil or raw diesel, so in a simple term the soot sample taken contains 8.34% oil or raw diesel contamination, the limit is 7.00 % ,
so the soot sample has failed our test as its over the 7% limit. In this term as we are over the 7% limit there is a problem with the car, whether it be over fuelling or leaking oil into the combustion chamber. As suggested in the attached case study several of this vehicles diesel fuel injectors did not pass OEM specification testes. 1 in particular was over 100% the required spec.

The next process in testing the soot sample is decreasing the temperature to 100 degrees, this is so we can cool the soot to a steady temperature, if we increase the temperature from 400 degree’s right after the previous 30 minutes there will be a chance we could burn the remaining soot too fast, once the temperature reaches 100 degree we hold the temperature their for 5 minutes forming our test base line.

We then increase the temperature to 700 degree’s and maintain this for duration of 9 minutes. The reason for doing this is to burn the remaining soot steadily leaving only a sample weight of other non
burnable contamination. You will notice there is a point at the end of this graph on the Green Y-1 line this is what’s left after the remaining soot is burnt. For example : the graph states 10.00%, this means 10.13% of foreign contaminate is left after the remaining soot has burnt, this will be due to engine component breaking up, for example piston rings slowly deteriorating or the burning of injector tips. The limit for this point on the graph is 2.00%, so again this has failed the test as it is over the 2.00% limit by 8.13%.

Conclusion Supplied by Independent Test Facility:

“After reading through the attached case study and completed a range of tests and examining the results we agree with the above mentioned study.. Our opinion after reading through this report is, the (redacted) Mazda Dealer purchased the vehicle with no evidence of any faults, once the faults were brought to there attention they only replaced the reported fault and no attention was made to any auxiliary components that could or indeed have caused the reported fault. The (redacted) Mazda Dealer took more attention to detail with their diagnostics and fault finding, but at this stage the DPF was already damaged, the correct procedures were taken to repair the vehicle however there has been no mention in the above document about the condition of the catalytic converter forward of the DPF unit (contained in the engine pipe) this is something that requires attention before replacement of
the DPF unit.”

Statement given by Independent Test Facility used to test DPF003SC.

Before you fit a new Diesel Particulate Filter (DPF)…

Before you fit a new Diesel Particulate Filter (DPF)…

Have you considered the following?

• Have you compared a picture of the faulty DPF with a picture of the replacement DPF?

• Check the vehicle history for any existing issues.

• Have a copy of the DPF Fitment Guide for the Professional – available from your local DPF supplier.

• Confirmed the reason for the apparent DPF failure, e.g. engine issues, injector timing, DPF pressure or flow, air leak, EGR, heater or glow plug, turbo engine wear.

• Inspect intercooler & associated plumbing for leaks or wear.

• Replaced the engine oil and filter, use low ash factory oil only.

• Check the used oil for any sign of contamination (thinning due to over fuelling/large clumps of carbon).

• Check the fuel for any signs of contamination e.g. water, bio-fuel or solids. Ensure low sulphur fuel only is being used.

• Ensure NO Bio-fuel has been used.

• Check catalytic converter efficiency, are there any signs of damage, heat discolouration or pitting of the substrate.

• Check all pressure and temperature sensors on the DPF.

• Purchase a new DPF fitment kit including gaskets, bolts and mountings.

• Ensured that no exhaust paste or silicone sealant is being used upstream of the DPF or Catalytic Converter.

• Re initialise Engine Control Units, reset ash level & adaptations and where necessary complete Engine Control Module restore.

• Check for vehicle Engine Control Module programming updates.
Check Adblue or Eolys (if applicable) at sufficient level.

• Completed a successful Forced Regeneration before driving the vehicle.

DPF Guide to Fitting for the Professional

DPF Guide to Fitting for the Professional



Please note this is only a guide and each vehicle present their own different faults and procedures, you must be competent and have the correct technical back up or you must take to a professional installer for this product.

Failure to follow the directions above will result in the DPF warranty becoming void!

For further technical help, consult the original place of purchase.

What to do when your customer shows up with one of these:

What to do when your customer shows up with one of these:


Diagnose the faults:

What caused the issue your customer is currently having? Diesel particular filters are a very precise emissions control that can be affected by even the slightest variation. When a customer arrives at your workshop with the DPF or check engine light on, here are the basic steps that should be followed.  Remember – DPF Removal is not the answer!



a) Vehicle History:

• Where and how has the vehicle been serviced?

• Have there been any similar faults diagnosed previously?

• Has low ash or genuine oil been used?

• What recent repairs have been made? E.g. Head gasket replacement, injectors, ECU reprograms.


b) Look at the stored codes, live data and check the following:

• Has Bio diesel been used?

• Over accumulation code?

• Temperature sensor codes?

• Pressure sensor codes?

> Check pressure differential sensor and lines connecting to the DPF for fractures or blockages.

• Air fuel ratio sensor codes?

• EOLYS injection codes?

• Low fuel pressure?

> This can be checked by the manufacturer or well equipped diesel shops.

• Diesel injector codes?

> Leakage can be a common cause of DPF failure and can be tested by diesel specialists.

• Variable vane turbo charger codes?

> Common part for wear and seizure due to high heat and soot.

• Examine live data e.g. temperature sensor readings, pressure differential sensor readings?

• Check EGR, including connection pipes and data transfer lines.


c) Ask some basic questions of the customer:

• Do you get out on the motorway or mainly city driving?

• Has the check engine / DPF light been on long?

• Have you seen the light before?

• What were you doing when the light came on?

WARNING: Removing DPF is illegal and will not solve the issue.

d) Look at the stored soot and ash percentages in the ECU:

• These will give a clear indicator of the severity of blockage and determine if the 80% rule applies.


e) Other contributing factors that may cause or be affected by DPF failure:

• Catalytic converter efficiency: The catalytic converter plays a large part in the way regeneration occurs. It is what creates the heat required to burn off the soot loading stored by the DPF. A physical check to determine that the catalytic converter is in working order and not melted or fractured is strongly recommended.

> Note: Catalytic converters can be separate to the DPF, part of the main DPF body and also incorporated into the DPF monolith itself.

DON’T FORGET: There is no such thing as a High Performance DPF Filter.  If you are upgrading your exhaust system on your car fitted with a DPF, ensure the new sports system is a DPF-Back system.  Contact us before starting a job like this, as we can help you find the best solution.


a) This process should only be attempted if the stored ash and soot levels are below 80%. Completion of this process will indicate that the vehicle has not been driven in such a way as to promote scheduled regeneration (these requirements can often be found in the Owners Handbook). It may also indicate issue’s like stored fault codes or programming faults that are present in the ECU.


a) Refer your customer to a dealer / mechanical workshop to rectify or repair issues causing DPF fault.

b) Check for any outstanding campaigns or ECU updates that have become available.



a) The following process must be observed and adhered to when replacing a Diesel Particulate Filter:

• The engine oil and filter must be renewed with OE parts and liquids.

> Note: To do this the vehicle should be run up to operating temp and then the oil and filter replaced to the correct fill level.

• The new Zetti Emissions Diesel Particular Filter can now be fitted. The engine can not be started or run for any reason from this point until completion of the following steps. This new unit needs to be fitted using either the supplied gaskets kit or parts sourced OE. (Used clamps, gaskets, and hanger can not be used on a new unit.) No silicone sealant or exhaust putty can be used pre or post the catalytic converter or diesel particular filter.

• Reset the ash and soot levels stored in the ECU. All ECU updates and faults need to have been rectified before this process can be carried out. If you are unable to do this with current workshop equipment the vehicle must be towed to a dealer to have this process completed. The engine cannot be started until this has been completed.

• The engine can now be started, bring the car up to operating temperature and perform a regeneration immediately either static (forced) or actively (while driving at a set speed and rpm). If this process is not fully completed, i.e. it gets halfway through and ends or the DPF light is displayed after attempting this process, STOP immediately and recheck faults as there is still an issue with the vehicle.

• If the regeneration completes 100% then the vehicle should be test driven by the workshop for 50-100km before returning to the customer to ensure no further issues are found.

Warning! This is only a guide as to the correct way to identify and rectify issues found with the Diesel Particular Filter. Each manufacturer & vehicle may deviate from this process.

Failure to follow the above directions will result in the Zetti Emissions Diesel Particular Filter warranty becoming void.

For further technical help please consult the original place of purchase.


We are passionate about our Zetti Emissions program.  This website exists so Spareco can share their knowledge on the new vehicle emissions being introduced to the Australian automotive industry.  If you are reading this to find out what a Particulate Filter Diesel is, then great.  Or maybe you’ve just asked the question “How much for a DPF Filter?”  You might be ready to buy and just want to know the DPF Filter Price.  As Australia’s largest stockist of Diesel Particulate Filter’s (DPF’s), Close Coupled, Under floor and Manifold Cat Converters, you’ve come to the right place.  Give us a call (on 1300 493 884) or visit our online shop ( and ask for a quote on our DPF & Catalytic Converter Prices.  We want to help!