heroin187

I am new to this forum and to Mercedes cars in general. Anyways my wife's car started to go into limp mode about a month ago due to fluid leaking into the transmission connector. It was throwing the generic transmission code and the transmission speed sensor code. So i did some research on it and decided to replace the connector plate also due to it being a little over 100,000 miles and that seems to be around when they start going bad anyways. So I bought all the tools need (and the maintenance dip stick) as everyone here has advised to do. I replaced the connector plate and flushed what i could out. I put everything back together , add fluid , and then warmed up the car to operating temperature. It would then only go into limp mode when doing a lot of city driving . So I thought I got the fluid level wrong and played around with that for a few days off and on but it would still go into limp-mode when it got hot and only when it was hot. Next I thought I might have gotten a bad connector plate so i installed a new one and its still doing the same thing. I car drive it to work and back on the highway and i don't have any issues even when its at operating temp. but when its stop and go traffic or city driving it will go into limp-mode. When i check the fluid level its warmed up to the point that it goes into limp mode and its in gear (drive) and its right in the middle in the min and max line. Am i doing something wrong, To much or to little fluid, or can it be something else?

Maj. Dundee

First of all it is very difficult to read a "uni" paragraph. Paragraphs, paragraphs.

Secondly, whenever you replace a transmission component, the "P" codes in the ECM and the 3 digit codes in the Trans. Cont. Module must both be erased. If you do not erase all codes in both modules, your limp mode will continue.

If you are only using a code reader that can produce "P" codes and not trans. codes as well, that code reader is useless. Below is the scanner you need.

heroin187

Sorry about the uni paragraph, on the computer it looks like its only 3 lines. The codes do go away ( at least i cant read them with a scanner )and I can drive it for days without it going into limp mode on the highway . It only goes into limp mode with a lot of city driving. I can turn the car off and then start it and its out of limp mode for awhile until it gets hot again.


My wife drove it on the highway for 40 mins and then 20mins of city driving a few times and no issues. When she does 30mins of just city driving it will go into limp mode. Is this a stored code that I will need the dealer to erase?

Maj. Dundee

What were the "P" code numbers. All of them.

heroin187

p0700 and p0720

Maj. Dundee

If those are the only two codes, then your code reader is not able to read 3 digit Trans. codes. You need a scanner like I recommended above.

These "P" codes stored in the ECM, only turn on the CEL to alert the owner that there is a problem somewhere in the veh. Since there is no separate light on the Inst. Cluster for the trans., it uses the CEL instead.

Please read the highlighted area relating to codes P0700 & P0720.