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Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4786
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
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2000 ML430 Mercedes.I replaced the transmission with a

Customer Question

2000 ML430 Mercedes.
I replaced the transmission with a used one and it keeps going into limp mode.
I Checked the PLUG their is no fluid on the plug.
Codes From TCM - 134 - 135 - 137
Submitted: 2 years ago.
Category: Mercedes
Expert:  Lou P. master tech replied 2 years ago.
were the same codes present before the trans swap?
Customer: replied 2 years ago.
Not sure, Coulden't Read TCM them, The Old Transmission was completely dead it would quit working within 10 seconds of start up like a bad pump.So i swaped it, Now this transmission works but it throws those 3 codes.
Expert:  Lou P. master tech replied 2 years ago.
ok, the 3 codes all relate to the CAN DATA BUS communication system, what codes are in the ME-SFI module ( engine ecm)? any?
Customer: replied 2 years ago.
Yea those 3 codes are in the TCM.. The ME-SFI module has no codes.Check engine light before had P0700 and P0720 . But now its just P0700
Expert:  Lou P. master tech replied 2 years ago.
ok, p0700 is for limp mode ( obviously ) does your shifter go to "D" or lower than "D"?
Customer: replied 2 years ago.
Shifter Gose into D..Sometimes Its weird when shifting it takes a Seconds to DISPLAY on the Gauge Cluster.
Expert:  Lou P. master tech replied 2 years ago.
ok that is what i am going after, the shifter is also a control module, it would be nice if you had a scanner that could read what the shifter is seeing, there is a mechanical linkage from the shifter to the trans which you know, but if the shifter and the trans gear selection does not match then the trans will be thrown into limp mode and it will not allow the trans to work properly, so you need to shift between all the positions and see if they match in the dash display
Expert:  Lou P. master tech replied 2 years ago.
also where did the trans come from? another ML? same year? do you have the dipstick to check the fluid and the scanner to read the correct temp?
Customer: replied 2 years ago.
I think another ML, it came out of a junk yard.Already Check Fluid with Dipstick Tool. Its All Good.
Expert:  Lou P. master tech replied 2 years ago.
the codes relate to the communication system like i stated, the problem is that the data bus is hard to diagnose without a mercedes style scan tool. there are 8 modules on the data bus , so you need a scanner to read all the modules on the data bus, engine module, trans module, shifter module, aam, abs unit. does your scanner read all those modules? also with those codes it kinda points to a failed trans module BUT without knowing what the other modules are seeing it will be a crap shoot.
Expert:  Lou P. master tech replied 2 years ago.
try to loosen the shifter linkage set screw and put the shifter and the trans into park and then tighten the set screw and go through the gears, if the display does not show correctly then you may have a bad shifter module, if there is fluid that got into that shifter like water or soda then it needs to be replaced.
Expert:  Lou P. master tech replied 2 years ago.
also look for a value in the scan tool for the trans module it should show what gear the shifter is in and what gear the trans is in, they should match, whichever one does not match correctly with the actual position is faulty. hope this helps . let me know if you need more info, hopefully you find a issue with something i suggested. let me know. Lou
Customer: replied 2 years ago.
Ill go check the linkage.
Customer: replied 2 years ago.
I shift cable looks fine, Even tho it shows slow, i dont think it would cause those 3 errors. Would it?
Expert:  Lou P. master tech replied 2 years ago.
Yes. As I explained already the shift positions have to match. I'm trying to give you things to check to save you from having to go to the dealer but anytime there is communication faults , you can't accurately diagnose without a dealer scan tool since the aftermarket scanners are missing vital information that the star diagnosis machine shows.
Customer: replied 2 years ago.
Can you please write out those 3 codes here for me.Also do they do match cause the car will move the the direction of where the guage cluster says and the shifter.
Expert:  Lou P. master tech replied 2 years ago.
Ok , I don't think you are understanding what I'm trying to say. I will have to opt out. Maybe another expert can help , sorry I won't be able to assist Furthet. I wish you luck.
Customer: replied 2 years ago.
If you are looking to opt out then do so, Im looking for someone to help fix it.Limp mode dose not happen all the time, Just now i drove the car around the block and its out of limp mode by itself, Only problem is that 10MPH the transmission will SHIFT kinda hard, it will jerk the car a little bit.After that it runs normal.
Customer: replied 2 years ago.
Well When you push pedal half way down, it will shift at 20-25 MPG but it seems like it will Slip for a second before catching.It hasent went into limp mode again yet but it it prob will.
Customer: replied 2 years ago.
Anyone Here to help?
Expert:  Lou P. master tech replied 2 years ago.
sorry noone has helped yet, the holiday may be a factor or the difficulty of the question.
lets try something, does your scanner have the ability to read the transmission ? or just the engine module?
Customer: replied 2 years ago.
It read all of it.The codes come up 134-135-137 for the Transmission.The Generic Codes come up p700 and P720. ( This came up with my old transmission )Im thiking of ordering a used ECU for the Transmission and trying that, If that dosent work then swap my valve body out into that transmission .The Car has not went into limp mode yet. It just shifts pretty hard into FIRST GEAR.Im think its either1. Transmission ECU
2. Valve Body
3. Transfer Case Motor?
4. Used Transmission is bad .What do you think ?
Expert:  Lou P. master tech replied 2 years ago.
Here's what I think. The transmission will learn to the trans and shifts will adjust. So when you change the trans it will still be shifting per the old trans adaptation. So see if your scanner can read the adaptation value. And it has to erased and relearned. So you see a actuation for that ? With your scanner. ?
Customer: replied 2 years ago.
You think the transmission is just shifting hard cause of the adaptation values?Ill have to check Monday when i go back the the shop.If you had to switched one thing what would it be? Since it seems like a electricl problem.It could only be1. TCU
2. Valve Body/ Conductor Plate?
3. Transfer Motor?
Expert:  Lou P. master tech replied 2 years ago.
No transfer case motor. That simply does nothing but lo gear or high gear.
I would say tcm only because it will have zero adaptation values and the trans adaptation will relearn. Every time a module or conductor plate or trans is replaced or repaired the values must be reset. You may be right with your repair but still have the old adaptation causing issues. Also the scanner needs to erase the fault codes from the tcm specifically. If not the codes will cause a limp function. Hope this information helps. I don't want to leave you hanging so I am trying here.
Customer: replied 2 years ago.
Well i did clear out the TCM codes and they came back after replacing the transmission.I did not clear Adaptation Values,. Now Since the codes are pretty much can bus errrors.I am kinda pointing towards TCM, Or Valvebody/Conductor plate. But then again i cant be for sure.
Customer: replied 2 years ago.
Im Reading the Mercades Manual on these codes.Codes 134 Says Replace TCU if not codes are stored in Traction system control module .
Code 135 Says See DM, Engines ( CAN: Engine management communication faulty )
Code 137 Has no Info. Says ( CAN: Communication with transfer case control module faulty )
Expert:  Lou P. master tech replied 2 years ago.
Ok. I seen the same from the service manual. But here's the thing. Why did the codes come in the first place. If they were not there before the trans was replaced then something changed. And it had to do with the new trans. Now can bus errors can come for different reasons. If there are can bus errors in the tcm then there has to be another module with can bus codes to relate.
Customer: replied 2 years ago.
Okay Heres a Update, So i relaized that the shifter would not let me use the slap stick to go threw 1-2-3-4.It seemed like the selector rod was too long for the transmission itself, i ended up griding the selector rod and now i can easily go threw 1-2-3-4 like it use to beSo now im thinking to clear the codes and test it. Do you think the codes could be from that?Transmission still shifts hard into first.
Expert:  Lou P. master tech replied 2 years ago.
Oh my. Did I not say something about the shifter rod about 200 posts back ? Why on earth did you fail to mention that. I honestly am not sure what to tell you at this point. Every time I suggest something you come back at me with a opposite suggestion and idea. And now with left out information. It is really hard to help this scenario.
Customer: replied 2 years ago.
Still Having Problems!I CHANGED THE TRANSMISSION to another 1.It SHIFTS smooth now! It still will go into limp mode with Generic Codes P0700 - P0720 I can only Assume its the Same Transmission Codes as before.Also ABS CODES C1022 C1024 C1140 C1401 .Seems Like It has alot of Fault In Communication Codes?
Expert:  Lou P. master tech replied 2 years ago.
I am going to opt out. I honestly don't know how to help you from here and I don't want to waste your time. Hopefully another expert can assist Better than I have. My apologies.