I have read on here of people having issues with the Anti-shudder valve (ASV), also known as the Intake Manifold Flap. It is an issue where the small plastic cogs inside break causing the flap mechanism to jam. This in turn blows the fuse and throws a fault.
Recently a mate's car had this issue which gave me chance to do a little investigating. He had already replaced the ASV at this stage but was still getting the EML. This is is scan and probably what others may see when the ASV decides to die.
3 Faults Found:
19558 - Motor for Intake Manifold Flap (V157)
P3102 - 000 - No Signal - Intermittent
Freeze Frame:
RPM: 798 /min
Torque: 46.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 13.98 V
Bin. Bits: 11000100
Torque: 158.0 Nm
Torque: 0.0 Nm
19557 - Motor for Intake Manifold Flap (V157)
P3101 - 000 - Open or Short to Ground - Intermittent
Freeze Frame:
RPM: 819 /min
Torque: 44.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 13.98 V
Bin. Bits: 11000100
Torque: 158.0 Nm
Torque: 0.0 Nm
17075 - Fan 1 Control Circuit
P0691 - 000 - Short to GND - Intermittent
Freeze Frame:
RPM: 798 /min
Torque: 48.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 13.83 V
Bin. Bits: 11000100
Temperature: 44.1°C
Duty Cycle: 9.6 %
Readiness: 1 2 0 0 1
This was on a a MK5 Golf GT 140 (BKD). I did some digging around and found that it would blow the fuse when it jammed up (Fuse 8 in the engine bay). So checked that and found it had blown. Replaced and cleared the faults and all was well again.
I asked if he had the old ASV as I wanted to take it apart to see what actually fails. This gave me an opportunity to get some photos so those on here can see inside one if anyone was interested in why these things fail.
There is only one way into these unit and that is to prise the grey metal lid off with a screwdriver. When manufactured it is put on the peened over in a few places to hold it in place.
Once opened I could see straight away what had happened. As suspected some teeth had broken off the gear (arrowed) that drives the flap causing it to jam.
And another.
Recovered the 2 broken teeth.
Where they came from.
Another photo of the inside.
I think I made have also found out why these fail. Once I managed to get the lid off I found all the inside was full of that black oily residue you get in the TDi intake. Was loads in it as you can see.
I believe this oil is forced by the seals on the shaft of the manifold flap due to being under positive pressure. This then causes the plastic to go brittle and break. Unfortunately I would say this cannot be repaired and a new one is the only real way of sorting it.
Hope this may have given some an insight and a reason as to why you have just had to fork out for a new one
