DPF Removal And Procedure Guide

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Here you will find a general guide to the process of removing a DPF (Diesel Particulate Filter) from a vehicle.

A vehicle must be diagnosed correctly, selling DPF removal as the solution to all sins is not competent. In 90% of cases a DPF failure is consequence of another component failure; simply removing the DPF will not resolve origin of the issue and compromise your reputation.

The DPF overloading or blocking is as usually a result of the following component failure or issues;

  • Air regulation fault; EGR, and or turbocharger boost circuit issue. This is the most common of causes of DPF failure especially on vehicles fitted with an airflow meter. Any leak or air bypass plays havoc with the DPF regulation and regeneration due to the mixture regulation problems. Some ignorant tuners claim that vehicle with no DPF will smoke and this is normal, this is not the case. It is the origin fault showing itself. Sad but true.
  • Fuel Injector failure; Worn nozzle/needles are common place on high mileage vehicles, again causing mixture regulation issues over loading the DPF system.
  • No smoke No poke; Ignorant injector duration remapping is pretty much a death sentence for any DPF system. Smoke = wasted energy

Our calibration files are developed and implemented thousands of times over the years and checked by our server’s mega data system for precision.

PCW hands on guide.

Firstly find out the story from the customer about their vehicle. Find out exactly what has brought them to you for a dpf removal, as an example consider asking questions like:

  • Has the vehicle been diagnosed by another garage before it came to you?
  • Has anybody else before you, physically done anything with the vehicle in regards to the ecu or the DPF exhaust unit?
  • How does the vehicle currently drive?
  • How long has the customer been driving it around for in Limp Mode?
  • What warning symbols appear on the display?
  • What is the current oil level?
  • Have they had any recent components replaced? etc..

Before we start here are few examples of the most common faults we see when a DPF Fails:

EGR Valve Failure


Turbocharger Failure


Inlet Manifold Swirl Flap Failure


Injector Failure


A very poor Ecu Re-calibration


Vehicle Diagnostic

  • Now that you have plugged your diagnostic tool into the vehicle and checked that it is only the DPF that is blocked and by removing this it will cure the problem then Proceed to the first step.
  • It is recommended that you scan every module on the vehicle and erase every fault code possible prior to working with the ECU
  • Attempt a forced regeneration always before removing the filter, this will exit the passive control cycle of the ECU.
  • This procedure will help to prevent post removal issues. Reset the (Particulate Data) Ash Counter.
  • Do Not Under Any Circumstances Skip This Step!
  • You must use the correct level of diagnostic equipment that suits that specific vehicle.
  • If you do not reset the ash counter prior to writing on the Mod File then you will en-counter problems such as the vehicle could remain in limp mode or it might not distinguish the light on the display, or it may not allow you to delete any DPF related fault code's as the gateways to them will be closed.

Read The ECU

  • OBD Tuning:
  • Plug in your Flash tool and take a read of the Original calibration file from the ECU.

  • ECU Removal:
  • If you have just switched off the ignition then it is advised that you let the communication network go to sleep.
  • Remove the key from the ignition, place it away from the vehicle and leave it for at least 3 mins.
  • Now remove the ECU, open and take read of the original file.
  • Upload the original file to the PCW Server and Calibrate your file. DPF/EGR switch OFF = DPF/EGR DISABLED

Remove, Modify And Re-install The DPF

  • Remove the Dpf exhaust unit from the vehicle.
  • Make sure all of the sensor wiring is unplugged and you do not damage the sensor's whilst removing it!
  • No place it on a surface where you can work on it and not damage any sensors you may have left plugged in.
  • For the best result and to any avoid MOT problems extract the DPF discreetly as possible do not cut a small square window.
  • TIP: An SDS Drill with a chisel bit, can be a great tool for breaking up the filter.
  • Check the condition of the pressure sensor's.
  • Weld the exhaust back up professionally.
  • Whilst the weld repair is cooling down check the rest of the exhaust assembly for any leaks,excessive corrosion and the condition of the gasket's (seals).
  • Depending on the vehicle now could be a good time to check the turbo for excessive wear?
  • Once the welding repair has cooled enough for you to be able to work with it and you have all the necessary clamps,gasket's and sealant at the ready you can now put the Dpf back on.
  • Again be-careful not to damage any sensors whilst re-fitting the exhaust! Do not start the vehicle.



Flashing The ECU

  • OBD Tuning: Plug your OBD flash tool into diagnostic port and write the Mod File into the ECU.
  • BENCH Tuning: Flash the Mod file into the ECU, check the surface of the Circuit board, reseal it and plug it back into to the vehicle.

Check The Vehicle

  • Start the vehicle and check the exhaust for any gas leaks.
  • Let the vehicle idle for 10-15 mins. Now plug in your diagnostic tool and scan for faults.
  • If you are clear then test drive the vehicle and allow it to get hot.
  • If you are happy with everything then perform the full and final diagnostic check prior to releasing the vehicle back to the customer.