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DPF Removal Problem

19824 Views 8 Replies 3 Participants Last post by  TalonTsi90
So I just purchased a 2006 Mazda 6 Sakata 2.0 Turbo Diesel.
Within the first week of driving the DPF light started flashing on the dash. This caused a huge loss in power, especially when climbing hills (So much that I can't even overtake a bus) however the vehicle still appears to run fine.. Still starts perfectly, Still able to drive in all gears fine. It's just very slow and take a long time to get up to speed.

So I contacted the Dealer who was surprised as he told me that the DPF had been removed and that it shouldn't be the problem.
Anyway he told me to take it to his Mechanic who removed the DPF originally free of charge as the Vehicle was still under warranty.

So I did.
They plugged their scan tool in and cleared the DPF in about 20 minutes and I drove off.

The car ran perfectly. I had all my power back and everything ran sweet for the next 3 days. Until it came back on again...

So I took the car straight back and they did the same thing and it was fine for another few days until the flashing DPF came on again!

This time I took it back and said I want it fixed permanently!
So they had the car for about a week and when I went to pick it up he told me that the problem will never come back and that the vehicles ECU doesn't recognise that there is a DPF on the vehicle at all! even much so that a scan tool wont even recognise DPF as a feature when you plug it in.

So I took it for a drive and the DPF light was gone (both when you put the key in the ignition and when you start it) which was good I suppose.

The car drove no differently. It still had no power at all, still struggles up hills bla bla bla. So I drove right back and explained to him in a very angry manner.

He told me that he had done his job and that the DPF is fully removed from the electrical side of the vehicle however the actual DPF unit was still in the exhaust and that's why it runs like it does (which I didn't know as the dealer told me it had been removed). Anyway he said that his job is done and that they only specialise in the electrical side and that the hardware side would have to be removed at an exhaust shop.

I told him that's weird as every other time I've come in, they've cleared the fault and its always run perfectly apart from the fact the problem comes back within a few days and that the problem must be his "electrical" side!

Anyway after a long argument we came to an agreement that I would get the DPF removed from the exhaust and if the problem was still there that I would bring it back to him to fix free of charge.

So I did! I got the DPF removed along with its sensors and pressure lines attached and the car ran no different. Even with DPF, sensors and pressure hoses removed the car ran no different, no lights on the dash, no power bla bla..

So I took it straight back to the mechanic (Who has the car right now as we speak)

I called him about an hour ago for an update and he told me that he has plugged his scan tool in and that the vehicle is showing no fault codes and all and that he is trying to figure out what is wrong with it.

Anyway just wanting to see if anyone on here has any ideas as to what's wrong with it in case this clown can't figure it out??
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Its probably gone into limp home mode.

The sensors still need to be attached and working in most cases even if the regen cycle has been coded out of the ECU.

Leaving the DPF installed is not an option as it will just clog up with soot and eventually will block up the exhaust.

The Cat and filter are in one unit, so what you really need to do is cut a door into the top of the filter housing (filter is in the back half) pull out the filter core and then weld the cut piece back in and re install the cat & housing plus the sensors.

There are three temp sensors which need to function as well as the two pressure sensors.
Sometimes if the temperature sensors go faulty then the car will go into limp mode.
The front one is the most likely suspect, but new ones are not cheap.
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Sounds like the changes your mechanic has made puts the car permanently in the warm up phase.
As soon as you mentioned calibrate temperature sensor - This was the clue.

This a crude way of avoiding a DPF regen cycle as the ECU will never trigger one in the warm up phase. I don't know what other problems are caused by this.
I have heard of places doing this as a 'fix'

The proper way to do it is to code out the regen cycle from the ECU. You need to find someone who can download the ECU code modify it and re upload it to the ECU.
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