cmpcpro

Hey guys, what's the best way to get my TCU out? It seems sandwiched between the fuse box and the actual fuse panel. Should I be disconnecting the battery first or can I pull up the fuse panel and get to it that way? Seems there is that little gold arm on the front of the fuse block that I can pull back and I assume the whole block will come up? Thanks!

E42AMG???

No need to undo the battery. Unplug the two harnesses and it will pull up.

Plutoe

That is very bad advice, disconnect all power-----and by the way why are you doing this?

cmpcpro

I replaced the TCU with a tuned one from DTK. They too said there was no need to unplug the battery, there is no power going to the TCU with the car off. On top of that WIS shows to pull the codes and then unplug it as I said, with no mention of unplugging the battery, so I'm not sure why you said it's bad advice. It's based off exactly what MB says to do, although if it would have involved moving the SAM anymore than the inch I did I probably would have disconnected just to be safe.

Plutoe

I am older than you and taught differently. I'll FA with the ex wife's car but not mine or a customers!

cmpcpro

Oh I agree on being careful and my instinct was to unplug the battery to be safe but MB said not to in WIS and electronics wear the most when power is introduced to them so if I don't need to according to the manufacturer I feel safe.

E42AMG???

I've done it multiple times no issues.