Help please, V157 fault diagnosis

[Overdose]

Edit: The fault was almost certainly wiring damage, but I have since sold the car with full disclosure, so it was never fixed.

Morning all,

I have a fault which appears to be common on VAG TDi engines and that is the V157 No signal error.

My VAGCOM kit is currently out of action, as I have no Windows laptop, so my diagnostics are back to basics, so...

2007 Touran with 2L BKD TDi engine.

Fault - Engine management light on
V157 No signal
Glow plugs 1 & 2 inoperative.

I have so far replaced the Intake flap valve, the light cleared and is now back, but I don't know for sure if it is the V157 or not, as I can't use my VAGCOM kit.

Could someone please give me a few pointers for locations and voltages that I should be looking at on the wiring for the V157 and under what conditions I should get the voltages?

Thanks in advance.

[Crasher]

Check fuse 24 in the engine bay fuse box.

[Overdose]

Thank you. I've checked and just checked again to be doubly sure, but the fuse is fine.

I wanted to try to find the pin figures and run actual voltage and resistance checks ideally, as I don't think this is going to be a quick fix.

I don't know what signal is being looked for to give the fault, but that would help too.

Edit: As this is designed to stop engine run-on when the car ignition is turned of, is the valve only momentarily powered at shutdown?

[Crasher]

The valve operates as anti shudder AND diesel run away flap so in those respects only operates momentarily or in brown underpants situations but is used by the ECU as part of the EGR strategy to control flow.

[Overdose]

Does anyone have a link to the wiring diagram and possible locations for the earthing points?

[Crasher]

I tried to post the wiring diagram yesterday (I only have it is German) but as I am using my backup PC I struggled to turn it from a pdf to a Jpeg for posting on Flickr, private message me your email.

[Overdose]

It's been some time and I've only just got around to trying to clear the management light.
Anyway, the light will not clear and the fault still remains.
Intake Manifold Flap V157 No Signal P3102

Actions taken so far...
Intake flap replaced
12v Supply checked to be ok
Ground checked to be ok

Unfortunately for me, this looks to be a bit more of a nuisance than I expected. I have used the output test to check the flap valve motor and it passes that ok, so I don't know what the problem could be, other than one of the two purple wires going back to the ECU.