Transmission Limp Mode on 2003 Jetta

Greetings all. Got a 2003 Jetta auto throwing a 00264 code - solenoid valve 4 (N91): open or short to ground. This car is newish to me, so I haven't dived into it fully but I did change the trans fluid a few months back and it has run great the whole time I've had it.

I checked resistance of the solenoids at the connector on the transmission case, and they seem correct, but checking at the cable side of the TCM I cant seem to get anything, otherwise I'm incorrectly testing there (though every pin gives me no reading or oddball numbers). Because of this I suspect the harness, is this reasonable? I'm having a hard time seeing all of it, looks like I have to pull the air filter box and battery to really get at it.

This cropped up the same day I had a really hard time starting up in the morning, drained the battery, had it on a charger, then eventually jump started it. Seems a little too coincidental to me. My central locking module also will not communicate, though this problem began a few days earlier. Could this simply be a bad ground somewhere? If so where would I look? Other suggestions?

KansasCityTDI.com, CoolAirVW is the man.
Have seen posts similar to yours here, try this-
VW TDI Search Engine

The easiest and cheapest things to do are:


1. fully charge battery
2. clean and remount all the ground points you can find
3. clear TCM codes
4. remove air box and battery, and clean TCM connectors
5. remove & clean contacts (not MAF itself), and reconnect MAF



After that, it's harness/solenoid/valve body.

While the battery is out clean the ground under the tray.
If it's bad then anything that grounds to the body is bad.

Well, went through all the suggestions here on this warmer day and no dice. Still throwing a code for solenoid 4, still in limp mode, even after clearing codes. Something I did at least resolved the central locking module issue, that works again.


I didn't see any obvious harness damage, guess I'll keep tinkering.