EGR/MAF fault ?

[swil00]

Hi,

I am currently experiencing intermittent misfire/juddering issues on my 2.0TDI (BKD engine). The car juddered and died one night last week. The AA were called out and suspected a sticking EGR valve, but he could'nt find any codes. Revved the car a few times and took it for a run - all ok again !

I have a vag-com kit, so scanned the car the following evening and got:

17036 - Sensor Reference Voltage B: Too Low
P0652 - 000 - -

According to ross-tech, this points towards a MAP sensor ?

I didn't clear the code as the car was going into the dealer for a service the next day.

Mentioned the breakdown/AA theory when dropped off at the dealer. They wouldn't accept the code I had and said it would need to go on their diagnostic system.

Collected the car that evening, no codes were found by the dealer, but they checked the EGR operation. Said to be ok... The only thing they could point towards was a blocked fuel filter, which was replaced in the service.

Drove the car home (150miles) where it was fine for the first 30 miles, then started to miss/judder when using light throttle.

Scanned the car again, no codes !

Ever since the breakdown last week the car has intermittentally juddered/missed and ran rough at idle.

I plugged my vag-com in today to read specified v's actual MAF sensor readings. With the engine on, idling, I opened the measuring block (003) to find:

RPM Mass/Air Mass/Air Duty Cycle %

819 245 425 96.5

Once the throttle is depressed both values were the almost identical:

1911 255 245 36.7


When I left the engine to idle again for a couple of minutes, the values return to what were originally observed. I've read the the EGR system is disabled after two minutes, so that might explain the change in the duty cycle, but should the MAss/Air value's show different values ?

I'm assuming that the layout on vag-com is Specified MASS, Actual MASS ?

Any help is much appreciated...

[Crasher]

It sounds like you have an injector on the way out, I am doing quite a few on the BKD. You will have to wait until it registers a misfire code to be sure of which one it is.