w203 C320cdi 722.9 transmission problems!

JonathanC250

Active Member
Joined
Dec 11, 2008
Messages
313
Location
Essex
Car
2005 W203 C320 CDI
Evening all,

I've been having problems with the gearbox on my car for a while now, however I will start from the top and hopefully you'll be able to see where I'm at now.

Originally the gearbox was playing up, loosing drive, limp mode etc..
This was down to a faulty speed sensor on the conductor plate, which I removed and sent off to ecu testing to be repaired.
Once I got the conductor plate back, I reinstalled it to the gearbox, with a new filter and fluid.
I Cleared the codes and went for a drive, the gearbox was back to normal. (When I say normal, I mean it wasn't going into limp mode, or getting stuck in gear or loosing drive anymore)

Then the turbo actuator decided to stop working, so I got another one of them and fitted it, now the car was driving pretty well, lots of power, still however the gearchanges were a bit off.

From doing alot of reading, I found that the problems I was experiencing could be from not resetting the gearbox and then doing an adaptation, after getting the conductor plate repaired.
So I used my diagnostic computer, a Delphi Ds150e I think it is, and proceeded to reset the transmission and torque converter adaptations. Then I tried to set the torque converter lock up adaptation.

This is where the problems began , since doing this, the car now feels like its slipping the transmission quite a bit, and when driving steady at anywhere between 40 and 70, if the revs sit at around 12-1500 for a few seconds the car then starts bumping 3 or 4 times in quick succession, which I'm assuming is the torque converter trying to engage.
I'm also getting a noise that sounds like turbo flutter, when the car slips and then changes gear, I'm not sure if this is the torque converter making this noise or not.

Anyway, by trying to get rid of one problem, I've created another! From further reading, it appears there is a software update for the gearbox, that addresses the problems I was experiencing (Changing down to 1st while still moving slowly, harsh 1-2 and 2-3 shifts)

Can anyone please help me get this sorted, I have the car booked in with Mercedes, but when I Said to them I would like the gearbox software updated and the torque converter lock up re-calibrated, I was initially told there is not an update available and the need to do a diagnosis first before they can say if there is an update, or re-calibrate anything @ £176 per hour!

If anyone can shed any light or knows anyone who would be able to help in the Essex area I would really appreciate it

Thanks in advance, and sorry for the long post!
 

AndrewOl

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Apr 1, 2017
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320
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Romsey
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GL420 X164
Sounds like you need to find a decent Indy with Star to look into the setup of your tcu. Setting the adaptations on these boxes is fairly involved and it does sound like yours is off somewhat. Hopefully someone will point you in a local Indy direction. Main dealer may not be the most cost effective solution. I live in Hampshire so can't make any recommendations for Essex.
 
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JonathanC250

JonathanC250

Active Member
Joined
Dec 11, 2008
Messages
313
Location
Essex
Car
2005 W203 C320 CDI
Thanks for the reply’s guys, I have actually used Alex in the past, he done the fluid and filter change on my old 202 C250 and got a couple of broken glow plugs out too. I did call him last week I think it was, and unfortunately he told me it’s stealer only! The phone line was terrible though and I couldn’t hear what he was saying exactly, but I got the part where he said it was dealer only!
 
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JonathanC250

JonathanC250

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Joined
Dec 11, 2008
Messages
313
Location
Essex
Car
2005 W203 C320 CDI
Does anyone happen to know if this software update actually exists for the early 722.9 gearboxes, and if you have had it done to your car, did it make a difference ?
 

AndrewOl

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Apr 1, 2017
Messages
320
Location
Romsey
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GL420 X164
There are different versions of processor fitted within the tcu. The software within it is ‘programmable’ via star. This is essentially what is happening during the adaptation process as I understand it.
 

wongl

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May 29, 2005
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Surrey and Hong Kong
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A180CDI, B200d, C300h, SLK250
Why do you think a firmware update will solve your problems when the gearbox worked 'normally' prior to the problems with the replacement of the turbo actuator?
 

Aleksejs

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Mar 22, 2019
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Latvia
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ML 63 AMG W166
It can be plenty problems
It can be solenoids
It can be hydraulic unit pressure loses
It can be frictions wear
It can be tcu malfunction.
Torque convector also maybe problem.
 
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JonathanC250

JonathanC250

Active Member
Joined
Dec 11, 2008
Messages
313
Location
Essex
Car
2005 W203 C320 CDI
Why do you think a firmware update will solve your problems when the gearbox worked 'normally' prior to the problems with the replacement of the turbo actuator?

Because it behaved normally after I replaced the turbo actuator, but because I had a faulty turbo actuator when I had the conductor plate repaired, I couldn’t carry out the reset of the gear adaptations. But from what I’ve researched, the way my diagnostic tool has done it would appear to be wrong. It is since doing the adaptation and recalibration of the torque converter lock up that these new problems have started. I was asking about the firmware update, as I’d read that this sorts the issue of rough 1-2,2-3 shifts and stops the car shifting back into 1st when slowing down, until it’s completely stopped.
Thanks
 

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