2.0 Tdi Bkd G40 Cam Sensor Implausible Signal Car Won't Start

Luckily this happened as I was pulling up to my drive. I actually scanned the car yesterday to demonstrate to a friend and it was fault clear.

The car was normal then all of a sudden I stopped at the junction to pull in my road and it felt and sounded weird, a bit grumbly, but anything over 1.8k ran and sounded fine.

I pulled on the drive engine still running and pop the bonnet, it sounded like the exhaust manifold had come off slightly or something and I had a look and nothing.

Turn the car off and now it doesn't start just turns over and over.

VCDS reports 16725 camshaft position sensor G40 implausible signal.

I unplugged it and the error changed to 19463 - no signal. It actually sounds like it's nearly going to run with it unplugged too.

Back plugged in and you get 16725 and eternal turning over.

I have got a G40 cam position sensor coming to Audi tomorrow morning and will be trying to change it, it looks fiddly as hell but I must try.

If the new sensor doesn't work where do I go from there?

Cambelt kit is genuine and only a few months old too. Cam timing doesn't look to have moved and it all of a sudden happened when just at idle, not revving it's head off.

I hope it's just the sensor, I'm sick of spending fecking money on fixing this car I just want it right aaaaaggggghhhh

Great, well I'm gonna have to see, it does look like "how am I supposed to get this plug through there" though

It's the sensor under the front cam pulley with the wire that goes to the front of the engine. Am I going to be able to do this without taking the belt etc off, internet seems to think its possible without removing anything?

Got a lot worse today, the car got started up again and I immediately saw the cambelt looking worryingly loose, then heard ping sounds so I've shut it off, close inspection reveals the tensioner has come way loose and I think the belt has now jumped loads and caused interference. F*ck

The sensor was an issue though, as the error became no signal, the new sensor cleared the fault with no reoccurrence.

As the car was going somewhere on Monday for a separate issue I extended the wires temporarily, ensuring the extension was secured way clear of the moving parts. I did not touch any of the timing gear.

The car got recovered this morning and they've said the culprit is the tensioner, they are fixing it for me as the cambelt was done there only a couple of weeks ago, head off etc and fix all damage. They're stacked though so I'm in a courtesy car for a couple of weeks.

I do actually trust that he did the job properly, I've known him for years and he has OCD about doing things right we'd all be proud of.