Tranny Limp mode?

[Hixrs6]

Hey everyone

So long story short I got a tranny limp mode a month or so ago and it puts me in 4th gear

Restarting the car it will usually disappear then reappear within 5-10 minutes of driving.

Used Vagcom and found code solenoid 3 (N90) short to ground.
Ordered all new solenoids but they sent the wrong
6,7,8 solenoids so while I was sourcing the correct ones I switched the failing solenoid from position 8 to position 7 AND the code switched to solenoid 2 N89 short to ground telling me it was in fact the solenoid.

Got the correct ones in and after 20 minutes of driving BAM back in limp mode.

What I’ve tried:

-Ensuring correct ATF levels/clean etc
-Checking TCU and cleaning the connectors with contact cleaner (no corrosion) however I do get some dampness in the passenger footwell carpet from time to time
-checking the reading between pin 4 and 16 on the harness at the front of the trans (reading fine) and cleaning that connection


I’ve read a ton of forums on this but feel at a loss, any help is much appreciated

[Shoppinit]

What was the fault code when it went back into limp?

[Hixrs6]

00262 - Solenoid valve 3 (N90): Open or short to ground
00260 - Solenoid Valve 2 (N89): Open or Short to Ground

Mainly it’ll be solenoid 3 but sometimes it’ll just say solenoid 2.

TCU box was clean and no sign of water under the carpet
Checked my pollen filter and saw it was damp underneath so I made homemade cover for it.

Testing the pins on the connector and getting a correct ohms reading shows me that the solenoid is okay though ?

[Shoppinit]

Maybe the solenoid is dead and it had burned out the input on the TCU. Then when you moved it, it burned out the other input, too.

If your carpet is wet, though, I'd definitely want to fix that first and I'd suspect a damaged TCU.

Could also be a harness issue inside the gearbox. Maybe there's a short occasionally.

You could log the TCU currents while driving to see if anything funny happens.

[Hixrs6]

I’ll give that a try this week, thank you for the help Shop.
Even after a battery reset, before the limp mode comes it takes a while to shift into 3rd and it quick slams in and out of 4th. Hard to say but Ill get those logs soon

[Hixrs6]

Maybe the solenoid is dead and it had burned out the input on the TCU. Then when you moved it, it burned out the other input, too.

If your carpet is wet, though, I'd definitely want to fix that first and I'd suspect a damaged TCU.

Could also be a harness issue inside the gearbox. Maybe there's a short occasionally.

You could log the TCU currents while driving to see if anything funny happens.

I have my buddies Vagcom, do you know off the top of your head how I can log TCU currents on it?

Thank you! Also here is my new fault code list. I’m starting to believe what you said about the input burning out because at first it was just solenoid 3 (N90) and then I moved it to solenoid 2 (89) to see what happens and that one is throwing a code now too.