Prince Gitau

Hey guys I'm having an issue with my Allroad C5, its a 2.5Tdi with the AKE engine and 5HP-19FLA (01V) Transmission Code EYJ.
Firstly it begun by having the PRNDS light on intermittently, then after a week it stayed permanently. Periodically the foward gears don't respond and now the car has sluggish foward but fully responsive reverse gear.
What I've tried so far;
>Changing the ATF
>Changing the Strainer
>I inspected the TCU and found it all corroded-took it out and after fitting it back it failed totally. Totally corroded inside. I'm getting a replacement TCU. Though on running further troubleshooting tried moving the car without the TCU connected still has responsive Reverse and still no foward gears..
The TCU was on the verge of dying just needed to be shaken abit for it to. Though that's not my main prob. Since the issue is still present without it in place.
Any pointers..?

jjrichar

If the TCU is completely corroded, then it is probably your issue. Even without the TCU connected, the transmission will work.

There is a manual selector valve in the transmission valve body that is directly connected (physically) to the gear lever. If you select a forward gear, and there is no input from the TCU and solenoids, it will put it into 4th gear. When you select reverse, it will be put into reverse. This is limp mode, and is the backup to get the car to a place to fix it when you have a problem (normally electric).

This would explain why it is sluggish going forward. Having had my car go into limp mode before (due to an electrical fault), the first thing we noticed before any warning lights was how gutless it was going forward. There is no indication of it being in 4th.
You can disconnect all electrical connections to the transmission and you can still manually select these gears.

Prince Gitau

Thanks jjrichar for the info. I'm partly relieved. Does that also result in the jerking when either Reverse or Drive gears are selected?
I'm really hopping my Clutches are in good shape...

Irish1004

I have experienced limp mode when my TCU was shorted out. It will cause sluggishness in drive and also jerking or hard engagement especially in reverse. Essentially you'll be stuck in 4th gear and hence RPMs will be much higher than normal. Once my TCM was replaced the transmission worked like new.

jjrichar

As stated by Irish, the engagement is very rough due to no electronics being involved.

Prince Gitau

Thanks guys for the shared wisdom... Got my replacement TCU fitted it into my Allroad and now she runs like new... No codes, smooth gear engagements and shifts.

Irish1004

You might want to check the drain under the battery box and remove any leaves or debris as a precautionary measure. Also the sunroof drains as this is how water enters the car on the passenger side soaks the carpet and eventually corrodes or shorts out the TCM. Glad you got it solved!

Prince Gitau

First thing I did was checked all drain points.. Thanks for the additional tips.. Just wonder why Asian cars don't have these issues... You know, this is German it should be perfect...
All is good I dint have to tear apart my tranny...