Hello, does anyone know of a low cost code scan tool that can get a 1998 E320 out of limp home mode? I replaced the conductor plate/speed sensor and changed the fluid, but it's still in limp home mode.
I cleared all code using the cheap scanner that I have and now it doesn't show any trouble codes, but it's still in limp home mode. When changing the conductor plate does the ECM firmware have to be flashed? or is there another way to fix this?

Thanks in advanced for any help.

 

What "cheap scan tool" did you use? And you need to provide more information about what you did and when this happened.

If you have the 5G transmission, it does not need to be coded to the car, as far as I know. But it may need adaptation.

A vehicle that old my need early versions of XENTRY called DAS or even HHT. I have had a lot of luck using the BenzNinja Club. You can search the threads for BenzNinja's contact info.

 

It sounds like you’ve already done a lot of work on your 1998 E320, and you’re on the right track addressing the conductor plate and clearing codes. However, a cheap scanner often won’t cut it when it comes to Mercedes-Benz vehicles, especially older models like yours that may require deeper diagnostic capabilities. Limp home mode can be triggered by multiple factors, even after replacing the conductor plate. One potential issue is that the transmission adaptation values may need to be reset, or the Transmission Control Module (TCM) may still have stored fault codes that a basic scanner cannot access. Additionally, while it’s rare, the ECM firmware typically doesn’t need to be flashed for a conductor plate replacement, but the system does need to be properly reset and initialized.

For your specific situation, I would recommend using a full system scanner that works well with older Mercedes-Benz models, like the YOUCANIC full system scanner. It’s an excellent tool because it not only reads codes from all systems, including the TCM and ECM, but it also allows you to reset adaptations and perform system-specific functions. Since your car is a 1998 model, you’ll need the 38-pin adapter to connect to the car’s diagnostic port. This will give you access to the data you need to pinpoint the issue and fully clear limp home mode. I’d also suggest double-checking the transmission fluid level and ensuring all electrical connections to the conductor plate are secure. With the right tools and a bit of troubleshooting, you should be able to get your E320 back to normal.

 

Thank you for the reply. These are the two scanners I've tried. One has 16 pins the other has 9. Both can read speed sensor codes, but can not reset the TCM. I've tried disconnecting the battery and touched the cables together to force a capacitor drain. It didn't help. The YOUCANIC bi-directional scanner is around $450-$500 which is out of my price range. Looks like the only way to get the TCM reset is to find a local garage and pray this is the problem.

 

The transmission is the 772.6 RWD. The trouble code was P0715 input/turbine speed sensor malfunction. I replaced the conductor plate, fluid and filter, the old fluid was in pretty bad shape. Now I just need to get it out of limp mode. I cleared the code and drove it around the block still in limp mode to see if the code would return, it does not, so I assume that was the problem for not being able to shift to a higher gear or maybe it takes time for the code to show up again, I don't know. I'm a it confused as I read the forums and some say the TCM has to be reset while others say once the problem is fixed it should simply come out of limp mode on it's own.

 

https://www.kingbolen.com/launch-x43...ybach-sprinter

 

An E-class built after 03/97 is equipped with DAS3 CANBUS electronics. That uses a 38-pin connector to communicate with the electronic modules. The OBD2 port in the DAS3 E-class vehicles does NOT fully communicate with all of the modules; you must go through the 38-pin connector over the front SAM under the hood on the driver's sider. The transmission will remain in limp mode until you clear the TCM via the 38-pin connector. You need a more versatile and upgraded diagnostic tool.

 

When my '99 CLK 320 was stuck in 2nd gear it was the computer. It's under the right footwell. I bought a replacement on ebay for I think less than $200? It was maybe 15 yrs ago but fyi. No need to program it, you just have get the correct computer, which the seller knew based on my VIN. Easy peezy.

 

Thanks for that info. I just checked and it was manufactured 3/97. I also found the input inside the firebox in the engine compartment.

Is it possible to use a launch cpr123 obd2 scanner and get a 38 pin adapter? Or is it a specific scanner that is needed?

 

I use a C3 STAR/HHT/Xentry diagnostic tool with the developer's kit for serious work down in the modules. For relatively generic stuff (like clearing codes) I use one of these:

FOXWELL NT530 for Mercedes Benz 38 Pin

A web search will find one. It can be used for both a 38-pin W210 and cars with OBD2. I would purchase one again and it is much faster and easier to use versus the C3 Mercedes diagnostic system.

 

Purchased the iCarsoft scanner from diagnostic world. It shows smog sensor code B31, TAC-Fault code 2, Y66/1 Reversing and Park solenoid short circuit or no communication and TCM fault code 7. The delayed crank started happening at the same time car went into limp mode. Somethings telling me its either the TCM or the ECM. The auto shop wants $400 to continue researching the problem plus $175 for the tow. If it turns out to need a transmission it just isn't worth it. I wish I knew if it was the transmission or the computer. I was really praying this scanner would have told me what was wrong with it. If the auto shop can figure it out I know I can't.

 

I had the car towed to a repair ship, they couldn't figure it out and have made it even worse. Now the it wont even go into drive until it is shifted into reverse and then into drive. The shift park solenoid is still not working and the car still has a delayed crank. Sometimes it will crank within a second , but most times it is about 20 seconds before cranking. The dash was working for a few days and then went back to being scrambled. I'm actually thinking maybe it is the computer. I thought for sure the new scanner would tell me what was wrong with it, but all it gives is a code 7 and Y66/1 reversing park and park lock solenoid short circuit or no connection. I wonder if it could be the shifter since it does seem to be electronic.

 

How old are the battery/batteries?

 

I would check the wiring. I once had problems with an Audi and it turned out that some rodent chewed through the wire going to the shift solenoid in the transmission.

 

I just swapped my conductor plate (CLK55) and here's the story I posted this morning...
http://barndogtrucks.com/2025/10/29/...t-barn-solves/

Hope it helps. I used the youcanic UCAN-2-C scanner