Question about Transmission Range Sensor and TCU

[wickedintention]

So I bought a used 2007 A4 Cabrio a few months back. A couple weeks ago, the CEL came on and the gear indicator panel flashes sometimes but other than that the car drives fine. I bought an ODBII reader and the code was P0706...transmission range sensor. I cleared the code then drove the car and the CEL came back on within the hour. After doing a ton of research on the interwebs, I thought I was dealing with a situation where one of two parts could be causing the problem:

1. TRS - which from my understanding is a part attached to the side of the transmission housing with a cable connected to it
2. TCU - which from my understanding is a significantly more expensive part located under the carpet inside the vehicle

I read that these parts are dealer only so I called my local Audi dealer to get prices for them. The parts guy told me that unless the vehicle is a Quattro, the TRS is incorporated into the TCU and that the TCU would have to be replaced as a whole.

I've had occurrences in the past with my motorbikes where the guys on my forums knew a lot more about the hardware than the guys at the parts counter. Not sure if that's the case here, but just wanted to get a reality check and see if the TRS and the TCU really are a single piece and therefore I need to replace the TCU (at a whopping cost of $1400).

Thanks in advance.

[Operator]

The TCM is in fact inside the Transmission. As for if the TRS and TCU are a single piece, that I'm not sure of. Also a used transmission is a much cheaper option....

Edited.

[mtroxel]

When you say TCU, I assume you mean the brains of the tranny. Mr. Bentley calls it the TCM and says it's under the ECM at the bottom of the windshield.

[Operator]

http://www.audiforums.com/forum/gene...5/#post1372405

[mtroxel]

^^^that thread is talking about the CVT trans. And Bentley says that TCM is inside the rear cover of the trans^^^ Are we talking about a 5 spd auto trans here?

[Operator]

^^^that thread is talking about the CVT trans. And Bentley says that TCM is inside the rear cover of the trans^^^ Are we talking about a 5 spd auto trans here?

My bad, I was thinking about the TCM, not the TCU.