HI House, this is a step by step guide on how I was able to fix my Audi A4 2002 model with fault code 17090 - Transmission Range Sensor (F125): Implausible Signal.

I fell in love with the VAG brand for no reason and my first car was a VW golf 3 1997 model. it was a superb car. and later on, I went on to get the audi a4 2002 model for my mum which as at the time I bought it, I did not know it had a transmission problem as I did not have the scan tool and I got the car based on the word of mouth of the dealer that it was good. coupled with the fact that it was a bit lower than the normal prices for a standard a4 of that model.

Fast forward to after I had it shipped to Nigeria, the dreaded PRND light cropped up on the screen and I did not know what to do about it as I contacted few folks here but I was not given the response I needed. I was able to do a few research and bought a VAG scan tool to diagnose the problem. I got the code 17090 and a host of other codes. But this one was more important as it concerned the gear. I looked it up on the Ross-Tech Wiki website and it fetched the following descriptions:

17090 - Transmission Range Sensor (F125): Implausible Signal

Possible Causes
Failed Multi-Function Transmission Range Switch (F125)
Wiring harness issue between F125 and TCM
Failed TCM
Shifter cable incorrectly adjusted

Possible Solutions
Inspect wiring harness between F125 and TCM, repair as needed
Replace Multi-Function Transmission Range Switch (F125)
Replace TCM
Check shifter cable adjustment
Check Measuring Blocks for F125 readings

Special Notes
When found in the VW Passat (3B), the Multi-Function Transmission Range Switch (F125) is adjustable, make sure it is set correctly as per repair manual.
When found in the Audi models with CVT (Continuously Variable Transmission), the Multi-Function Transmission Range Switch (F125) is part of the Mechatronic unit and cannot be replaced separately.

Following.

I'll be following this thread with rapt attention.

Kudos to the op.

redcliff:
Fast forward to after I had it shipped to Nigeria, the dreaded PRND light cropped up on the screen and I did not know what to do about it as I contacted few folks here but I was not given the response I needed. I was able to do a few research and bought a VAG scan tool to diagnose the problem. I got the code 17090 and a host of other codes. But this one was more important as it concerned the gear. I looked it up on the Ross-Tech Wiki website and it fetched the following descriptions:

17090 - Transmission Range Sensor (F125): Implausible Signal

Possible Causes
Failed Multi-Function Transmission Range Switch (F125)
Wiring harness issue between F125 and TCM
Failed TCM
Shifter cable incorrectly adjusted

Possible Solutions
Inspect wiring harness between F125 and TCM, repair as needed
Replace Multi-Function Transmission Range Switch (F125)
Replace TCM
Check shifter cable adjustment
Check Measuring Blocks for F125 readings

Special Notes
When found in the VW Passat (3B), the Multi-Function Transmission Range Switch (F125) is adjustable, make sure it is set correctly as per repair manual.
When found in the Audi models with CVT (Continuously Variable Transmission), the Multi-Function Transmission Range Switch (F125) is part of the Mechatronic unit and cannot be replaced separately .

Was urs the cvt model?

GAZZUZZ:


Was urs the cvt model?

yes its a CVT model. Well, according to the transmission code FSD, I was able to figure out it was one..

After this, I read an article online that explained the type of gear I have and it gave me an understanding of what exactly was wrong. I discovered that the Transmission control module (TCM) for the vehicle was faulty and many other audi cars have suffered this setback. this was the reason why A4/A6 from 2002-2004 was not so used in Nigeria and even some of them up to 2007, but I am not so sure.

I then looked online and went to the Audi office to find out how much a new one cost. I was told it ranged from 1k-2k dollars. This was not an option as it was too expensive. I found out a company in the united states that fix TCMs. www.shop.modulerepairpro.com/.

I contacted them and I discovered i could actually send my bad TCM to them to reconfigure and they would in turn send it bck to me. It has a warranty o a lifetime so I was guessing it was a good deal. Although it was a bit steep but it was totally worth it. $330 in total to repair and send it back to me. this was not including the cost of sending it to them. I was charged 18,000 by Fedex which took just about 3 working days to get to CA, US. it was fixed and sent back the same day. which was a good thing.

It took more than a week to get to nigeria coupled with the fact that it was with held just because of egunje. So i had to pay an extra 1k5 to get it from the post office. However i should note that removing the tcm is not the work of just any mechanic. Most mechanics around dont know much about this (according to my dealings with them).

One thing i advice people to do most times is that, if you have a problem with your car and you dont seem to trust the expertise of your mechanic, you should make sure you know enough about the problem of the car and solution paths before engaging their services. This is just personal experience and it works......

Anyway, i paid a total sum of 30k to remove and put back the tcm. However the audi a4 transmission fluid had to be replaced As it was super black. I wonder when the last owner did so. Some say the fluid can last for a lifetime and some advice that it should be changed after every 100k km. I strongly advice that it should be changed every 30-40k km, if its driven every 10k km per year, thats every 3-4years Which is not bad if you really need your transmission to last longer than it should.....

I went on to www.blauparts.com, they sell mainly vw and audi products and i ordered the particular oil for my transmissiom which was. A/T Fluid Audi G 052 180 A2 - Ravenol CVT (12). (Please note the alphanumberic characters in bold). It was specific to my CVT transmisson and i had them bring it to nigeria through a nairalander's logistics company "chinosxl".

With the right oil, the re configured tcm, i only just needed them to be fixed back by the specialist who took it out in the first place. I got his number on nairaland too. His name is abbey. He is a mechanic at the VAG mechanic shop in gbagada. you would see his details here once you search for it with the nl search bar. After evrrything that needed ti be installed was installed, according to him, an adaptation needed to be done, which was carried out the next day at his garage. While all these were done, the car was home serviced rather than being done at the garage because of the waiting time for all the necessaries to arrive.

And thats how i saved myself the headache of getting a new transmission as adviced the very first time, which cost so much..

BusinessHub1:
interesting.. Pictoral back-up would have made this more interesting Sir.. Still educating tho.

true but i was not close to the car at that moment. I was only giving instructions from where i was to the person who carried it out.