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I have a 2004 sl500 and it is in limp mode with abs disatronic and esp lights on. I put my scanner on it and I couldn’t get any info from the TCM like it wasn’t there. I took it to a local Mercedes shop and they said they couldn’t read it either and that it was a TCM problem. So I pulled the TCM and sent it off for repair. The company told me that it was fine just updated the software. I go to put it back in and the same problem. The mechanic told me the TCM was getting power and ground. Any ideas. It’s a 722.9 transmission.
ABS, Distronic and ESP would indicate the issue is in the braking system, not transmission. I'm not sure what kind of scanner you used but I know that on my Foxwell Elite, I have to have the engine running to get any readings out of some of these susbsystems. I get nothing out of them when the engine is off.
But I would start looking at your SBC and see if it's OK, then the ABS and ESP and so on. When your SBC approaches it's End of Life (as calculated internally), it starts giving errors such as you see, then eventually shuts down or fails altogether.
If your TCM is not in communication with the other systems, you definitely have an issue. Since you have presumably eliminated the actual TCM, I would look at the wiring to/from the TCM. On the 722.9, external wiring is pretty simple: power, ground, 2-wire CAN-C. Power is fed from K40/4f37 (fuse 37 in the passenger side under hood fuse box) to pin 4 at the transmission, ground is pin 5 at the trans to W37 (left footwell), CAN-C is trans pins 1 and 2 to the X30/18 terminal block in the left footwell.
1) check fuse 37
2) check for power across pins 4 & 5 at the transmission connector (red/black and brown wires)
3) check for continuity on CAN wiring and check condition of connection at terminal block
If your TCM is not in communication with the other systems, you definitely have an issue. Since you have presumably eliminated the actual TCM, I would look at the wiring to/from the TCM. On the 722.9, external wiring is pretty simple: power, ground, 2-wire CAN-C. Power is fed from K40/4f37 (fuse 37 in the passenger side under hood fuse box) to pin 4 at the transmission, ground is pin 5 at the trans to W37 (left footwell), CAN-C is trans pins 1 and 2 to the X30/18 terminal block in the left footwell.
1) check fuse 37
2) check for power across pins 4 & 5 at the transmission connector (red/black and brown wires)
3) check for continuity on CAN wiring and check condition of connection at terminal block
Mike
You seem to know about the TCM so I have a question:
Why would the TCM give out ABC, Distronic and ESP errors. Those errors and the car being forced into LIMP mode would indicate a problem in the braking systems, most likely SBC.
You should have codes or events stored on the systems that are not working. I'm not 100% sure, but I would guess that all three of those systems use readings from the transmission speed sensors (via CAN-C). Lack of communication with the TCU would leave them without necessary information to operate and they would be disabled.
The car was driving just fine, drove it to work and after about 8 hours i got into it and it was automatically in limp mode. do you have the color code of the wires and what the specific votage or ohms to the wires should be, when i get home ill check that fuse 37 i pray its just that easy..
When you say “got into it” and “limp mode” does that mean when you press accelerator pedal all the way down (wide open throttle)? Does restarting the car take it out of limp mode?
The car was driving just fine, drove it to work and after about 8 hours i got into it and it was automatically in limp mode. do you have the color code of the wires and what the specific votage or ohms to the wires should be, when i get home ill check that fuse 37 i pray its just that easy..
When you say “got into it” and “limp mode” does that mean when you press accelerator pedal all the way down (wide open throttle)? Does restarting the car take it out of limp mode?
my car goes into drive reverse but hits hard and it does not shift code is no communication with TCM went on vacation for a week came back and we’re she stands took it to Benz they said o it’s like a 7000 dollar job buy a new one great if I had it and battery is also draining someone said my auxiliary battery is bad? Think that’s the problem?
my car goes into drive reverse but hits hard and it does not shift code is no communication with TCM went on vacation for a week came back and we’re she stands took it to Benz they said o it’s like a 7000 dollar job buy a new one great if I had it and battery is also draining someone said my auxiliary battery is bad? Think that’s the problem?
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Hello all,
I'm chiming in because I have a similar issue. I have a 2009 R230 and the ABS ESP message, my car will not shift into gear, and my iCarSoft shows TCM not communicating/ the U0101 error code. I've tried getting to the TCM but on this face lifted version there are no pics, instructions, or diagrams to show where it is. I can't figure if it is the 722.9 gearbox TCM conductor plate that is in the transmission housing, or the A0275450332 part that is supposed to be located in the passenger side footwell. I opened up the footwell area and I didn't see a TCM on the side, or on the backside of the metal plate. Only thing behind it was the Harmon Kardon Subwoofer. If anyone knows where I can find the TCM proper on an 09 SL 550 I would really be grateful. I will take it into the dealer if all else fails.
A 2009 SL550 will have the 722.9 with the TCM integrated into the conductor plate. Start by checking power, ground, and CAN communication. You can also look up your diagnostic port wiring diagram and see which pin the TCM communicates on. Sometimes there is a problem with one pin on the port. Another option is to buy/make a cable for the TCM. You provide power directly to the TCM and read it with your scanner. The point is that you probably want to be sure that you have a bad TCM before you go to the trouble to remove it.
Thank you very much MikeJ, I'll take your advice and try to see what is going on with the TCM. Even though it says it isn't communicating, its possible it could be the power or a bad fuse or something else.
10-31-2020, 09:09 AM
