Some context to your issue may be helpful here.
Assuming this is on your 2009 CBEA Jetta, the only part you'll run into is the silly tamper-proof screws they put around the ECU connector. But if you take the little firewall insert out, you can get in there with an angle grinder and cut a slot in each one and if you work quickly you can back them out easy enough with a flat screwdriver. I say work quick, because the heat generated by the grinder will have softened the thread locker.
Then the ECU slides out and the connectors (there are two) come right off with the slide lock moved away. Standard Bosch ECU type deal.
You'll find though that the little tiny cavities for the pins are too small to fit much of any standard probe in without tooefing them and causing a problem that maybe wasn't there before. I usually use a tiny back probe pit and go in carefully from the BACK side, once the cover is pulled loose.