General: V50/S40 DPF or FAP filter removal

[Stew]

Hello,
Not sure if this subject has already been covered but I thought I would post it in case it is of some use to people.
I have recently been having problems with my 2.0 TDI 2005 Volvo V50 going into limp mode. I did a diagnostic check and found it was showing a blocked DPF filter. I tried cleaning the filter with jet wash, detergent etc which worked for a while but it soon started to clog again as I use the car mainly around town. Decided that instead of replacing the filter I would try to remove it all together. Now I must point out before I go on that I am not some sort of electrical/electronic wizard, I just did a bit of reading and came up with a solution.

As you will probably be aware, you can’t just remove the DPF and begin driving again as the pressure sensor for the DPF will show a fault. To prevent this from happening you need to fool the ECU into thinking that the DPF is working fine. This was not as hard as I first thought. The sensor for the DPF (attached to the battery housing) is fairly simple. It has two pressure pipes which are feed from either side of the filter, an electrical socket with a 5 volt live, an earth and an output wire which sends a voltage to the ecu. I worked out that if the ECU receives a voltage of approximately 0.35 volts it believes that the filter is working fine. I therefore cut the three wires feeding the sensor and fitted a 5k Cermet potentiometer (see below). These can be found at Maplin or eBay for under £1.50p

http://www.maplin.co.uk/Module.aspx?ModuleNo=2202

These simply allow you to adjust the output voltage from 5volts down to zero in very fine increments. I then soldered the earth wire to the earth connection of the potentiometer, the 5v cable and output cable to the remaining connections on the potentiometer. Once that was done it was just a simple case of setting the output voltage to the desired reading which is approximately .35 of a volt and clearing any fault codes from the ECU. I also took the DPF filter off the car and removed the carbon insert with a large drill.

The engine has run for a few weeks now with no pending or current faults on the ECU.

Like I said at the start, I am no technical guru but I would say that anyone who can use a soldering iron, multimeter and a large drill could do this and save a fortune on replacing DPF’s or having your ECU remapped.

Hope this is of help to someone.

Cheers,

Stew