Exhaust Pressure DPF

[mcskou]

Hi Guys,
ISSUE: When testing pressure on DPF I get negative pressure on acceleration and plus when decellerating. - If tops around 3000 rpm, and then engine light comes on, goes to limp mode.

After about a week, and 3 different mechanics, and 2 new "Exhaust pressure sensors" (OE: 8200974421) - Since it was a cheap version the first one (only 30€) the next mechanic decided that it was definately that and changed it for a more expensive more ( 70€ (bastard) - after running tests on the car, without driving it, he said, all is good, but got a new fault (P1641) which the other mechanics didn't get. I called him after I left and the limp mode was back on, and he said, you probably should clean the Particle filter then and glow plugs. (YEAH RIGHT!! - I need some more reliable reason before i do that)

I am at a loss of app 200€ and I have no idea what to do.

[calnorth]

I think a neg pressure is wrong...but I'm no big expert on DPF problems. Someone who is explains a lot on the subject in the video attached. Principle is the same. This video is about too much back pressure ...or pressure across the DPF. In this case its a new non OEM DPF that had been fitted. Temperature sensors monitor the state of the DPF. This car has a DPF "limp home" mode fault related to DPF problem.

I suppose you had been advised to do a DPF Regen?

P1641 appears to be related to coolant temperature after engine start...has someone damaged a wire to that sensor...?