Exhaust Gas Temperature Sensor NO 1 Missing A4 B7

[Anco]

Hello All,

this is my first post on the forum so thank you all for having me.

I have tried searching for any posts which already cover this topic but could not find any. If it has already been covered please feel free to let me know. I tried scouring the internet for an answer to this but an not find anything.

So here goes.

Around 2 months ago I purchased a A4 B7 2.0 TDI 140 (BLB engine) with 130000 miles on it. It seemed to have good service history (although most of it was not by an Audi dealer) and be in clean condition.

Until this week it drove fine and seemed to be working ok, we have covered around 2000 miles in it so far. It had an MOT this month and passed, the only advisories were tyres being a bit low.

On the way to work yesterday the minimum oil level warning light came on. I feared this was the oil pump failing, which I believe is a common problem. When I checked the oil level it was low, and once topped up the warning did not reappear on the drive home.

Last month I tested the oil pump output pressure, which reached 5 BAR at around 4000rpm.

Once home I put the car up on a set of ramps and checked for any oil leaks. During this I found that there was a slight covering of oil below the turbo, which appears to be coming from the oil return pipe connection, the feed pipe looks well sealed so hopefully the turbo has been receiving a good supply of oil. I believe the car has also had an EGR blanking plate fitted, if that is relevant.

The turbo has obviously been worked on before, as the airbox was not properly secured, and more worryingly (and the purpose of this post) I found a non OEM fitting.

In the attached photos I noticed a wheel bolt has been screwed into the turbo housing on the exhaust side. The photos are taken from the top side of the turbo. After some research I believe this is a boss for the exhaust gas temperature sensor NO 1 (Part number is possibly 03L906088A). I can not see any sensor hanging free or an empty electrical connection.

My main questions are:

1) Would the temperature sensor have been present originally? Am I correct in thinking some VWs did not have these? I believe this car does not have a DPF as standard.

2) Why would someone remove this sensor?

3) Will missing this sensor cause any damage or running issues?

4) What would anyone recommend to be the best action for me to take from now?

5) If the car did not have a temperature sensor, is there a correct blanking fitting for this boss?

I apologise for the long post but hopefully it provides enough information for everyone, if I have missed anything important please just let me know.

Thanks in advance for your help,

Anco.