Volkswagen Passat Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Hi everyone. I just bought a 1999 Passat v6 2.8l with tiptronic 5 speed transmission front wheel drive. The carpet on the passanger side was wet and the TCM was open, even the plastic box was broken. The transmission display shows all the positions highlighted (limp mode) for a brief periodo and then goes off, sometimes not even comes on, but when you disconnect the battery and reconect it again, first it shows is in 2nd, then R, then P, then N and then all. But I hear a little click sound and the "press brake" light on the selector lever pulsates along with the transmission display and then it goes off. As the TCM was already open, I dryed the dampness with some rice but nothing seems to change. The car is stuck in 3rd gear and everytime I change into R, I can feel a hard stump, the same as changing into D. Tiptronic does not seem to engage when I move the selector lever to the right and the transmission display stays off. Do I have to replace the TCM? As a note, sometimes i connect the obd2 diagnostic tool and it gave me P1626 code and sometimes does not show any codes at all.
 

·
Registered
Joined
·
9,544 Posts
Check the TCM PCB for corrosion, also check the contacts in the TCM connector, clean all with contact cleaner.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Check the TCM PCB for corrosion, also check the contacts in the TCM connector, clean all with contact cleaner.
The PCB has some cracked varnish in some places, there is 4 small PCB soldered to the main PCB, those ones have the peeled varnish and some mud like sediments. The contacts on the TCM connector are clean, I cleaned it with contact cleaner and a toothbrush. Didn't work.
 

·
Registered
Joined
·
9,544 Posts
That seems like corrosion on the PCBs, that conductive and needs to be cleaned.
Then spray with silicone spray, or lightly cover with silicone grease.

Also clean the connector contacts where the wiring connects to the transmission.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #8
I replaced the TCU and now shows new codes, P1625 and P1749. Do I need to program the TCU in order to function properly and do I need to use VAG COM?
 
1 - 8 of 8 Posts
Top