C220CDI Auto query

[Paul Rickards]

Hello,
I have a new C220 CDI (1500 klm) which I am very happy with but there is one thing I am concerned about. When cruising slowly under light throttle (as in traffic) the auto will change down until top gear is reached but it is too slow for the gear and vibrates just as you would expect if it was a manual. I can accel away and it immediately changes down to the correct gear but it is very disconcerting to feel the car vibrating and you cant always accel away when in traffic! does anyone have any thoughts? cheers, Paul

 

[rf065]

Hello,
I have a new C220 CDI (1500 klm) which I am very happy with but there is one thing I am concerned about. When cruising slowly under light throttle (as in traffic) the auto will change down until top gear is reached but it is too slow for the gear and vibrates just as you would expect if it was a manual. I can accel away and it immediately changes down to the correct gear but it is very disconcerting to feel the car vibrating and you cant always accel away when in traffic! does anyone have any thoughts? cheers, Paul

I take it you mean "change up until top gear is reached"?
Mine is opposite it always changes down to a lower gear when going slow.

Russ

 

[Paul Rickards]

Yes, sorry for the confusion, it changes up till it is in top gear which is too high for the speed of the car

 

[rf065]

Mine has never done that. I don't think it should either.

Russ

 

[st13phil]

Paul, I too have a W204 C220 CDI and I don't recognise the symptoms you describe. Can you be more specific about roadspeed and rpm and I'll try to replicate the condition? Also are you driving with the transmission in C or S mode?

 

[Paul Rickards]

Hello Russ and Phil, thanks for your replies and sorry about the delay in answering, I live in Melbourne Australia so there is quite a time difference! Phil, I would certainly appreciate you trying with your car. I have noticed the problem mostly when I have had to slow down in traffic so I am already in top gear. Once the car is down to around 40kph with light load on the throttle the RPM drops down to about 1100 RPM. This is when I can feel and hear the vibration. If I just lightly accelerate the RPM goes straight to about 1600RPM (has changed down) and the vibration disappears. It doesnt matter if I am in C or S.
hope this is clear enough,
cheers,
Paul

 

[st13phil]

Hello Russ and Phil, thanks for your replies and sorry about the delay in answering, I live in Melbourne Australia so there is quite a time difference!

Paul, the other way of looking at this is that we don't answer you very quickly because of the time difference

Back on topic, I'll try to replicate your driving scenario while I'm out and about today and will post back with what I find.

 

[rf065]

Paul, there is a thread on the other forum which seems to mirror your problem?

http://www.mbclub.co.uk/forums/showthread.php?t=47253

Russ

 

[Paul Rickards]

Russ,
it certainly sounded the same at first but now I am not so sure because mine is never so bad as to shake the wheel, it just vibrates due to being in too high a gear. If I meet an incline and just lightly increase the throttle it changes down and the vibration disappears,
Paul

 

[st13phil]

OK, I've just been out for a drive and my W204 doesn't exhibit any of the symptoms described by Paul. The following all references kph rather than mph because it's easier to keep the speed units the same! My testing was done with the transmission in C mode, but a quick run in S mode made no discernable difference.

On coast-down from, say, 100kph the box downshifts from 5th to 4th at approx 67kph and as the speed drops further the rev's drop apparently to idle speed (~900rpm) at about 40kph. I can't notice another downshift either audibly or by watching the tacho, but if I touch the throttle very lightly at ~40kph just enough to maintain speed it's clear that the box has already shifted to 3rd and the rev's rise to approx 1,400rpm.

There is another thread here that seems to describe a similar issue to Paul's in which Black55 usefully posted an MB Bulletin regarding adaption of a torque converter lockup clutch. Sounds like a visit to the dealer may be in order?

BTW, when was your car built, Paul? Mine was built in decade 2 of December 2007, but I only took delivery in mid-January. Currently it has approx 1,650 miles on the odo.

 

[Paul Rickards]

Thanks Phil,it was very good of you to take the time to experiment with your car. I will print off all these posts and take them to my dealer to discuss the problem with them. It looks like a software update might fix it! My car was also built in Dec.07 and delivered on Jan.15th 08. Thanks again Phil and Russ for your help, it certainly shows the benefit of a great forum like this, hope I can return the favour to someone in the future,
cheers,
Paul

 

[Paul Rickards]

My car is booked in for next Wed 20th with my local M.B. service centre. Will let you know what the outcome is, hope they have a fix,
Paul

 

[st13phil]

Thanks for the update and I hope you get a resolution. Please keep us posted.

 

[Paul Rickards]

Just a quick update, the MB service centre has been checking my car for over four days now! Fortunately for me they do agree that it does have the problem I have explained. They have updated all the software to no avail so then they tried replacing the transmission valve body. I have just picked up the car and there does seem to be an improvement. I will be driving the car on holidays in Tasmania for 10 days so will give it a good test to report back to them. In the mean time they are waiting to get there hands on another new C220CDI to compare. Will give a further update when I have more news,
cheers,
Paul

 

[st13phil]

Thanks for the update, Paul. It seems you have two things in your favour at the moment: 1) The dealer agrees that you have a problem, and 2) they are actively trying to fix it!

Enjoy your holiday in Tasmania and please let us know whether the issue has been cured.

 

[Paul Rickards]

Hello Phil,
yes I was very relieved when they agreed they could also feel the vibration and they are doing there best to find the solution.I will certainly let you know the outcome,
cheers,
Paul

 

[Paul Rickards]

Well I am afraid I dont have any good news, except we had a great holiday in tasmania! The car drove beautifully on the country roads but when going through any towns and caught in traffic the problem was still there. The local dealer is now telling me they have driven another C220 CDI and it is the same and also head office tells him it is normal!I have told them I am extremely disappointed but somehow I dont think they will be persuing it any further. It seems to me that the new engine has so much torque (400Nm) and they havnt spent enough development time matching it to the 5 speed auto, just a gut feeling.Not sure where I can go from here, sorry I have no solutions for anyone else experiencing this problem
cheers
Paul

 

[st13phil]

Glad you had a great time in Tasmania. Not so glad that you still have the vibration problem.

Something to pose to your dealer: They have now driven two examples that exhibit the problem (yours and another); I have an example that doesn't exhibit the problem. I know it's a small sample size, but on this evidence it obviously isn't "normal", otherwise mine would do it too.

Have they gone through the lock up clutch adaption procedure detailed in the bulletin posted by Black55 (as mentioned earlier in this thread)?

 

[Paul Rickards]

Hello Phil,
I will check with them tomorrow about the lock up clutch adaption procedure although I havnt noticed any jolting it would be worth a try. If I dont have any luck with them I will be trying another Dealer,
Paul

 

[Rory]

It seems to me that the new engine has so much torque (400Nm) and they havnt spent enough development time matching it to the 5 speed auto, just a gut feeling.

400Nm's! I had to check that, but it's correct!!

But I have an older C270CDi and that has 370Nm and the box copes just fine. And, I would imagine, the same box was used for the 320CDi before they switched to 7 speed.

I hate this "they all do that, sir" attitude with Mercedes. My W203 drifting left is beyond annoying (mine's "better than most" - in that case I'd hate to drive a bad one). And COMAND's sat nav constantly gives instructions late when I drive it, but when the dealer drives it then it's fine.