| ETC is under passenger side footwell. You turn and a remove a few fasteners (one is behind a small plastic tab, another part of the vent on the tunnel. Pull back footwell carpet, not to the seat, just the upwwardly angled part closest to the firewall (this is not MB procedure - they say you'll "damage" the foam padding. Once you discover it is completely soaked with trans fluid that came out of the connector at the trans and walked up the wire, you won't worry so much about it). TCU id the box closest to the pass door. You'll see a metal plate. Three plastic "nuts" hold it on, then it will come off. TCU is the box closest to the pass door. Expect lots of fluid. Disconnect neg. battery cable, unplug two tcu connectors. Spray over and over with rubbing alcohol (again - not exactly a WIS procedure, but it will get you there at much less money than the 25 cans of elec. contact cleaner you would need otherwise). Not a bad idea to pull the padding too. Should be replaced, but I just sprayed the crap out of mine. Finish with contact cleaner. If your model doesn't have the TCU mounted with the connectors facing the floorboard, drill a couple of holes and spin it around. Some genius at MB thought this would help stop the fluid from climbing inot the box. What it does is give the fluid a place to collect. If the plugs point down, gravity will pull the fluid back out when unpowered (the current is what draws it up). Of course replacing the o-rings on the trans harness will usually stop the whole thing.
I had three different shops tell me I definitely needed a new TCU, and probably a new shift assembly. Multimeter tests at the TCU showed it was getting a good signal, and $5 buys a lot of rubbing alcohol (make sure you use 98%). Worked fine ever since. Probably just lucky - but I'll take that anyday. |