Transmission ECU
05-27-2019 | 12:27 PM
#1
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cl500
Transmission ECU
I have 2000 S430 with funky shifting transmission ? I had conductor plate replaced but it still shift funky I assume ecu got transmission oil in it can I just replace it with used well know part or it needs coding. Where is the ecu located it seems it is in engine compartment passengers side.
05-27-2019 | 06:06 PM
#2
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Joined: Dec 2012
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
You can almost always clean the Transmission Control Unit and take care of the problem.
Buy a spray can of good "brake and parts cleaner" - Don't try to save a dollar here...
Under the hood, find the right SAM (Signal Acquisition Module), the sealed black plastic box at the right rear corner of the engine compartment. Remember that left/right on a vehicle is ALWAYS from the standpoint of a seated driver - i.e., the right headlight is always on the right side of the car, even though it is on your left side as you are standing in front of the car. The right SAM is under the lower right corner of the windshield!
Open the SAM (two sliding locks), and carefully examine each of the wire harnesses inside for any traces of oily residue (ATF). If you see any oily residue on one of the harnesses, gently wriggle and tug on that harness to pull the TCU out of the SAM - it will be a black plastic box about the size of a pack of cigarettes.
Protect your eyes - goggles are much better than glasses. Nitrile gloves are a good thing.
Carefully pop open the TCU, trying hard to avoid breaking any of the tabs. Use the brake and parts cleaner to thoroughly clean all traces of ATF from the electronic board, the connectors, the inside of the box, and the wire harness. Let it dry completely.
Reassemble the TCU and work it back down into the SAM.
It may take a few trips for the TCU to relearn what to do. If this solves your problem, it will probably be good for several years. It would be a good thing to do a permanent fix by replacing the TCU connector on the lower left rear corner of the transmission - reasonably cheap at a Mercedes Benz or Dodge dealership, reasonably easy to do, and you lose very little ATF during the replacement.
Buy a spray can of good "brake and parts cleaner" - Don't try to save a dollar here...
Under the hood, find the right SAM (Signal Acquisition Module), the sealed black plastic box at the right rear corner of the engine compartment. Remember that left/right on a vehicle is ALWAYS from the standpoint of a seated driver - i.e., the right headlight is always on the right side of the car, even though it is on your left side as you are standing in front of the car. The right SAM is under the lower right corner of the windshield!
Open the SAM (two sliding locks), and carefully examine each of the wire harnesses inside for any traces of oily residue (ATF). If you see any oily residue on one of the harnesses, gently wriggle and tug on that harness to pull the TCU out of the SAM - it will be a black plastic box about the size of a pack of cigarettes.
Protect your eyes - goggles are much better than glasses. Nitrile gloves are a good thing.
Carefully pop open the TCU, trying hard to avoid breaking any of the tabs. Use the brake and parts cleaner to thoroughly clean all traces of ATF from the electronic board, the connectors, the inside of the box, and the wire harness. Let it dry completely.
Reassemble the TCU and work it back down into the SAM.
It may take a few trips for the TCU to relearn what to do. If this solves your problem, it will probably be good for several years. It would be a good thing to do a permanent fix by replacing the TCU connector on the lower left rear corner of the transmission - reasonably cheap at a Mercedes Benz or Dodge dealership, reasonably easy to do, and you lose very little ATF during the replacement.
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pierrejoliat (05-30-2019)
