c3002008

I noticed recently especially on cold mornings that the shifts are not smooth and at times it feels hesitant. Once I did the TCU reset my car is back to normal. So can I rule out mechanical issues (tranny,TC,etc) since it went away with the reset? Maybe it needs a software update?

abqhudson

How do you do a TCU reset?

ghlkal

Unfortunately the TCU reset doesn't solve the problem read post 1 here
https://mbworld.org/forums/c-class-w...tle-delay.html


TCU Reset

Read post 1 here (secret #10)
https://mbworld.org/forums/c-class-w...ts-thread.html

jlr82

Yes, doing the TCU reset does improve shifting and I do it at least once a month when I start noticing the shifts aren't as smooth anymore. Anyone can say what they want about whether it works, but in my experience I notice a HUGE improvement every time I do it in shifting.

c3002008

yes there is a definite difference after doing the TCU reset. What I was asking was that if the shifts goes back to normal after the reset then it means that there are no mechanical issues (transmission or TC) because if there was an issue then it would be present even after the TCU reset, correct?

jlr82

Correct, unfortunately this is typical characteristics of the C Class in general. I've experienced the issue on W203/W204/W205s. I don't know if it's because I do mostly city driving so I'm all over the place with the way I use the throttle, but I typically do it once a month or whenever I begin to notice consistent "bad behavior" in shifting.

jlr82

One thing I've also noticed that seems to help, which is the opposite of advice given here, is that whenever you do the reset, drive slowly and do a bunch of smooth stop and go operations with steady low throttle for a little bit after the reset. If I do that it keeps it smoother for a longer, or at least that's my perception after having fiddled with these cars for a couple years now.

c3002008

Ok I appreciate the advice. yeah at first I was concerned when the shifts seemed off and I was relieved once the car returned to normal after the reset. Next time I take my car in for service I will ask them if the software are all updated.

jlr82

When you ask them about it be sure to be persistent that over time you notice incorrect behavior. My dealer wasn't aware of the TCU reset procedure... so I'm not sure if telling them anything about that helps. I've found that with my Service Advisor that remembers me, and knows I'm very technical and keep my car in brand-new condition at all times will often appease my requests for software updates. Which reminds me I need to schedule an Audio 20 update they said my car had, and I'd also like them to check for the transmission control module update since I read on here that another 2014 C250 owner had an update applied.

MB Marko

you can also unplug the battery for 10 minutes and it will drive just like you did a TCU reset for a little while.

I have varient coding done, I love it. I was looking at getting a eurocharged tune also but talking to a fellow member they basically do variant coding and a little more, Im unsure of the more as they wouldn't tell me though email lol.

I'm going to get a price for the tune but i feel since i already have probably 50% of it done I shouldn't pay what they re asking for.

Colin G

What is the latest Audio 20 update? Do you happen to know what gets updated?

herbert68

Would like to know that as well.

jlr82

The dealer doesn't know what the updates contain, but I've complained about a few issues that happen at random and the last time I was there they said they checked for an update and one is available. They want to keep the car all day for it though because the updates have a high failure rate, and if the update fails its a long process for them to resolve.