B4, Error Code 65535 & Flashing Temp Light

I am getting this 65535 error code intermittently.
"Internal Control Module Memory Error"
I wonder if it is related to the occasional flashing red temperature light on the dash. I have just replaced the thermostat and oring, the coolant temperature sensor and oring, coolant T and oring, and of course the coolant. The flashing temp light on the dash, plus the original G 11 blue coolant, was the reason for redoing everything. The car never overheated or leaked or acted weird. But the problem of the flashing red temp light does not appear to be solved.
I have not yet disconnected the battery in an attempt to reset things.
Thoughts?

Most usual cause of this error is a split in the boost hose that leads into the ECU... often in the small length of hose inside the ECU itself.

For example:

http://forums.tdiclub.com/showthread.php?t=455587

but you should be able to find many threads on this if you search on that error code.

Re. TDI error code 65535

Thank you very much, Vince. I know better. I should have checked that long ago. I will report back here.

yea, boost leak or clog or split boost line in the ecu. had the same thing, twice, first was the line was cracked in the ecu, the 2nd time was some caked up oil crud made its way into the n75 valve

Re. TDI error code 65535 and flashing coolant dash light

I removed and replaced an old original vacuum line in the ECU. It then drove 85+ up Donner Summit.



The old hose looked totally fine. Blowing through the brass hose fitting going through the ECU case won't necessarily reveal a bad piece of vac tubing. Upon dissection, one end of the tubing had green gunk on it and, when squished, stayed completely flat. I cleaned the fitting until shiny and installed new tubing. Success! No limp mode, no more error code.



Flashing dash coolant light was a badly nicked wire on the expansion tank sensor. Repaired. So far no light. Thank you, gentlemen.

Yay! Thanks for reporting back... glad you got 'er licked!!

1Z TDI ECU vacuum line, CEL 65535