Remove and clean diesel particulate filter (DPF) (Articles)

This article describes the function, expansion, and cleaning of the non-additive diesel particulate filter (DPF) using the example of the 2.0 TDI 16V PD 140PS engine, engine code BRE.
The BRE engine was installed in the Audi A4 and Audi A6.
The basic functionality and procedure for DPF cleaning are identical for most other 2.0 TDIs with diesel particulate filters.
Immediately before removing the DPF, it must be forcibly regenerated using VCDS:
Forced regeneration of the DPF on VAG TDIs

Warning:A DPF that is inevitably clogged during normal operation (or is not burnt out) is not suitable for cleaning! When cleaning, only the ash (= burnt soot) can be removed with water, not the soot itself!

The diesel particulate filter consists of ceramic (silicon carbide, platinum-coated), i.e., mutually closed tubes that each form a block. Several of these blocks form the catalytically active DPF filter element.

Necessary parts
6 Cu-coated M8 nuts, N 902 002 01DPF turbocharger seal 3A0 253 115

Exhaust pipe-DPF seal 1H0 253 115
Heat-resistant paste

Diesel Particulate Filter ExpansionRemove engine cover.

Remove air intake and air filter top (2 Phillips head screws at the top of the grille).
Loosen the air intake duct to the turbocharger at the air filter box (screw clamp).
Remove the air filter and air filter bottom.
Unscrew the DPF from the turbocharger (SW12, M.
Disconnect the lambda sensor and temperature sensor inlet DPF wiring.
Remove the lambda sensor from the DPF, while removing the lambda sensor, pay attention not to damage the connection cable. It is best to make a loop (180° curve) 3cm after the sensor and attach the cable directly to the sensor while removing.
Unplug and remove the differential pressure sensor.
Remove the engine compartment cover.
Loosen the horizontal support of the exhaust pipe and move it to the side.
Loosen the vertical support of the exhaust pipe (SW16, M10).
Unscrew the DPF from the exhaust pipe (SW12, M.
Remove the AGR cooler from the catalytic converter and place it behind.
Remove the DPF.
Remove the differential pressure sensor with the hose from the DPF.
Remove the temperature sensor inlet DPF. Warming up the threaded connection helps. Location: Sensor outlet in the middle towards the lambda sensor connection.

DPF Cleaning

To ensure that only ash remains in the DPF during cleaning, a forced regeneration was performed using VCDS, and after its completion, the vehicle was immediately disassembled. It is optimal to drive directly onto a lift with the regeneration cycle almost complete (load value < 2%) and stop the engine. The goal of the immediately preceding forced regeneration is to burn insoluble filter components that make cleaning difficult. For example, sulfur or soot, which prevent cleaning with a solvent such as water.

The disassembled DPF is then cleaned with a garden hose in the opposite direction of normal exhaust flow. Be careful when using high-pressure cleaners, do not use a pinpoint spray on individual channels!

DPF InstallationImportant: Secure sensor lines, correct routing. Please ensure that the cables from hot parts of the exhaust system or exhaust bend are sufficiently removed and that any heat-protective sheaths are correctly placed.

Grease the M8 threads on the DPF with hot screw paste, use new Cu-M8 nuts.

Matching ash mass with VCDS

Engine control unit (ECU address 01), then select VCDS function "Adaptation/Adjustment". Enter the new ash mass in channel 12, calculation see VCDS label file, example see image below.
I have entered 4g as the new ash mass (DPF as good as new). Use the function to reset the ash mass on newer engine control units.

Value difference pressure
A list of which pressure values are considered normal can be found in the following topic:Pressure norm values at DPF of TDI engines

Further links, background information on the diesel particulate filterhttp://www.mie.uth.gr/labs/ltte/pubs/PhD_Stratakis.pdf

Background information on ash and sootUnfortunately, many readers do not distinguish between soot (carbon/carbon compounds that can be burned) and ash (combustion residue, what remains after soot, etc.).
The persistent rumor is that the ash can be "burned off" or "dissolved" with common cleaning agents. This is not so.





Ash consists essentially of various metal oxides and carbonates, which require very strong acids to dissolve partially (depending on the material!), so that the housing of the DPF would long have been eaten away.
The obviously sparse owners of a simple wood stove are clearly in a better position, because none of them would come up with the idea of dissolving ash in the stove with dish soap or emptying the ash box with a soldering iron.One cleans the ash box byemptying. One turns it over and pours out the contents. This is exactly what the reverse flushing of the filter capillaries in the DPF does.
Chip tuning / Tuning and DPFCaution with vehicles with DPF and poor chip tuning. While TDIs without DPF only suffer permanent damage to the turbocharger, here the DPF can also be damaged and its effect lost. Then it becomes expensive.



If someone has their vehicle modified, please ensure that no shoddy work is done and that the exhaust temperature and soot emissions remain within normal limits. For example, with VCDS, you can monitor the corresponding temperatures in real-time at full throttle and draw your own conclusions about the quality of the tuning.