Hey everyone sorry my first post is a request for help...

1996 A4 quattro automatic

This problem started with me getting no heat, and after reading through the forum I found out that clogged heater cores seem to be a common issue with the b5s.

I decided to flush the heater core but first I flushed the coolant as their was a lot of gunk built up in it as well.

After flushing the coolant/ heater core and refilling with some fresh coolant the heat was finally working again.

I decided to take her for a test drive around the block...

-When I put the transmission into reverse nothing happened

-All other gears appear to work fine

-After putting the car into neutral and pushing it out of my garage I was able to drive around without any issue


After reading all the no reverse related threads I could find it seems that the MFS (multi function switch) is the culprit and during the extremely messy process of flushing everything I must have got water on it or some how damaged it?

or possibly their is a sensor that is causing this?

Just seems strange that all other aspects of the transmission seems fine except reverse.

I would think logically if getting water on something was the problem that everything would not work not just reverse but I learned a long time ago logic and car problems don't always mix...

Thanks in advance for any help.

 

Update:

At first the instrument cluster was displaying incorrect gear position...

P=N
R=N
N=N
D=D
4=D
3=4

however now after just doing a few shifts to test it after switching into 2 now all gears are highlighted in the instrument cluster (limp mode)

As far as the codes I don't have a vag/obd scanner is there a way to check codes through the climate control units display?


I pulled up the carpet on the passenger side to check the TCU (Transmission control unit).

The foam under the carpet was soaking wet however inside the TCU housing as well as the actual TCU itself once removed were both dry and don't show any signs of water damage.

So its pretty obvious that somehow spraying water while flushing the HC/coolant went somewhere it shouldn't have and damaged something. I'm just not sure what??

Any suggestions on where to go from here?

I would really like to avoid buying an obdII scanner if possible I'm still unsure if there is a way to pull codes through on board diagnostics without using a scanner.

Is there a way to troubleshoot the TCU/ MFS without reading codes?

Thanks in advance for any help.

 

If you can take the car to Autozone they should be able to get the codes for you. Then you can post em here and im sure someone can look em up for you.

 

Its not a Chrysler , you need the codes..

However, that carpet being wet is a very good tell that water got into either the TCM and/or Multi Function Switch...

 

You might have blown the heater core by creating pressure while trying to flush it, making it leak and get water in the car.

 

I managed to get everything under the passenger side carpet in the TCU area dry. I then re-connected the TCU/Battery and tried starting her up and of course it's still in limp mode.


So assuming the cowl drain was clogged and water leaked into the car through the hvac would it make sense that the MFS would have got wet in the process as well?

If something did get wet it almost certainly is still wet as the cold air here in Canada makes things drying on there own very difficult.

How can I confirm the MFS is the culprit?

Someone had mentioned possibly "a short somewhere in the harness to the switch"
Where is the harness located I will trace from the harness as close as I can get to the MFS without having to take the transmission mounts off (I have nothing to support the transmission until possibly the weekend).


Is it possible that if there was a problem from the water in the TCU area which is now resolved from removing the water, that a code would need to be cleared first in order to get it out of limp mode?

I'm in a small town unfortunately there is no autozone to take it in for the free scan/clear I would have to purchase a scanner I guess if necessary.

Also I don't think the heater core is blown as it would be coolant under the carpet not water.

Any suggestions for further troubleshooting I would love to hear them.

I have to take the day off work tommorow with no ride, so plenty of time to mess around with it.

 

From what I understand from a previous post, and depending on model/year, the codes need to be cleared..

 

I guess I have to bite the bullet and get a scanner then..

Just to be clear this scanner should be able to read/clear any codes?

http://www.canadiantire.ca/AST/brows...1%2BReader.jsp

 

Use Vag-Com...

 

Ya.. for tranny and other Audi specific modules, you'll need a dedicated Audi/VW scanner.. not generic OBDII ones...They do make them