Mercedes 2005 C240 Stuck in 2nd gear

Joe Athey • 8 September 2019

I have a C240 Mercedes with 220k miles. I had the Drive in S (sport mode). I was putting along on a busy interstate and floored it to change lanes. As soon as I did this something seemed like it slipped and then it went into limp mode in 2nd gear. 
I drove it about 3 miles after that. I parked it and unhooked the battery cables and touched the positive and negative cables per the instruction of a friend. This was to get it out of limp mode and discharge any residual current that might be stored. I started it and it clunked going into reverse. I got it out on the road and it was still stuck in 2nd gear. 
I tried to drive it home about 70 miles so I drove about 50 mph in 2nd gear. Stopped to get gas and when I restarted the car it was in 1st gear. Tried unhooking the cables and let it sit for a while and could not get it to shift into 2nd, still stuck in 1st.
Took it to a friend who cleared all the codes and he told me 3rd gear is out of it and it needs a new transmission.
The car had been sitting for a week in my drive: I started it, put it into reverse (no clunking noise), backed it out and when I took off it was in 1st gear, it shifted into 2nd but still will not shift into 3rd. When I slowed down and stopped it did not go back into 1st it was again stuck in 2nd.
I have read through several articles on this page. Many state that it is probably not the transmission but electrical. Reaching out to someone who is in the know for a diagnosis.


Sorry to hear about your troulbes. You can't reset transmission codes by disconnecting the battery or with a generic scanner. You need a scanner that read Mercedes specific fault codes.

I would first inspect the transmisison connector for leaks. If that's ok, replace the valve body if there is a code for incorrect gear ratio.

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  • There must have been an issue with the transmission. Sometimes, it kicks into stay alive mode because of various reasons including low battery voltage. Have you tried replacing the battery? Maybe that would work well. 

    Also, check if there is any sort of leakage in the transmission connector as it tends to affect the functioning of the gear. 

    If everything above is fine then get the gear oil levels checked. Low gear oil levels do not let you change the gear or they simply slow down the movement of the gear. 

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