CLK 208 200 elegance auto problems ?

[CLKjohn78]

Hi everyone, This is my first time so please be patient !!
I,m desperate for some advice regarding an ongoing problem with my CLK200. Its only done 32000 miles and has always serviced properly by specialist garages using genuine Merc parts and quality oil .
I bought it 4 years ago with 13000 miles on the clock and its been brilliant up until now. Just before Christmas it started to clonk and jerk once presumably as the auto box changed down as you approached a junction. It didn't do it every time and sometimes it seemed as though the gear had not selected as you went to pull away. It then clunked as the drive took up. I was advised to replace the auto transmission oil with the geuine Mercedes transmission fluid also the filter. The old oil was clean as a whistle and apart from some minute carbon deposits in the filter there was no debris or swarf indicating any mechanical failures. The car now drives a lot smoother and the clunk/jerk has improved. I had the external transmission sensor with the "O" rings replaced with a new one even though it was not oil contaminated. The car was scanned, there were no suspicious fault codes that might indicate any gearbox problems. The MAF had recorded a fault in the past and the code was cleared, I was asked to drive the car for 200 miles or so we can see if the code returns and the MAF sensor needs replacing. Does anyone know if this is a MAF related problem or is it a gearbox problem? Its going back into be scanned on Thursday. As far as I know MAF is original and has never been replaced. I only use good petrol and the car is not modified in any way. Can you clean MAF sensors or shall I bite the bullet and replace it anyway. Thanks for taking the time to read this, sorry its gone on but I thought it better to include all the relevant information/symptoms.
Thanks , Regards

 

[television]

Hello John, where does one start.

First the changes from cold can be hard, and the car will hang on to the first 2 gears to warm up the CAT quickly.

Regards the MAF, this can and does affect the engine output in terms of BHP output, If the MAF is going down, then if the engine output is down a touch, this can affect the shift points, so that the box may not be sure of what to do.

Welcome to the MB forum

 

[CLKjohn78]

Auto problems ?

Thanks for your quick response,
I know it held onto the gears longer when cold. Its never done this before. This doesn't seem to be a temperature related problem it can occur at the start or end of the journey. if anything its worse when the car has warmed up. All the gears engage really smoothly up and down the box in auto or if i shift manually. I does not make any difference if its in winter or summer setting.
I have some mechanical knowledge and I always try to nip things in the bud rather than allow them to escalate.
Regards CLKjohn78

 

[Ellsy Tanners]

Hello and welcome the forum.
Yes it is very possible the maf is affecting your gear change slightly. If the fault has returned the I would get a genuine replacement bosch sensor.

 

[nodger]

Just before Christmas it started to clonk and jerk once presumably as the auto box changed down as you approached a junction. It didn't do it every time and sometimes it seemed as though the gear had not selected as you went to pull away. It then clunked as the drive took up.

Can you clean MAF sensors or shall I bite the bullet and replace it anyway.

Hi John,

I had the same problem with my CLK last year and the change of transmission oil solved it. It did take a few days following the change for everything to improve, but it was certainly running better than ever after a week.

Regarding the MAF - Parrot has written a guide here:

http://forums.mercedesclub.org.uk/showthread.php?t=25775

The MAF in a W208 is located at the front right-hand side of the engine bay.

 

[CLKjohn78]

Thanks very much for your suggestions. I think it is a forgone conclusion for me to replace the MAF sensor. At least that way it eliminates it. It does drive a bit flat so it might perk it up a bit. I hardly get to drive it unless it needs fuel or there is a problem, the wife loves it and uses it far more than me. I will get a Bosch one. Its going to get scanned again tomorrow and I will replace it after it is done. Thanks to both of you for your advice. I wish I had known about this forum before. I am really impressed by the quality of the advice and the friendliness of the members.
Regards John

 

[CLKjohn78]

As I stated yesterday the car went into get scanned today (Thursday) we scanned it whilst it was not being driven and also did a live scan whilst it was. It all pointed to the MAF sensor it was showing very low voltage even when being driven hard under kickdown. We then live scanned an old C200 saloon with over 150 thousand miles on the clock to match the data readings of the MAF and its gearbox performance. Everything pointed to my MAF being defunct so we drove to the local Bosch spares shop and for just under £140 secured a new one. This was duly fitted and off I went. (There was no physical sign of any oil or other contamination on the sensor wire on the old MAF and the air filter housing is clean and dry with a very clean genuine filter fitted. ) The car is definitley more responsive and it drives much more crisply. However as soon as I slowed down for a left turn "Clunk" went the gearbox exactly the same. Having spent over £400 quid on it has anyone got any ideas what to try/replace next. I have just disconnected the battery and will leave it for three hours before re connecting to alleviate any stored glitches and allow the car to re learn / accept the new MAF. I,m guessing the only thing to do next is to replace the sensor plate deep in the bowels of the gearbox. My friendly specialist tells me they are about £150 plus about £100 labour.
He does about 4 of these a week on Mercs and they normally cause completly different faults to what I,m experiencing and show up as conclusive fault codes on the scan . He,s therefore reluctant to relace the sensor plate until it throws a proper wobbly and puts the car into limp home mode. Any ideas anyone ?????
Regards John

 

[television]

John,,£145 from a Bosch service center or £250 from MB

 

[CLKjohn78]

Thanks Malcolm. This will probably be my next step. I do like the car and its so nice to drive I,m reluctant to just put up with it. I just know its causing more damage. I feel almost obliged to keep it nice. The original owner of the car was a very highly decorated WW2 pilot who was the first person to destroy a "U" boat with a Liberator bomber and a "Leigh" light. He was shot down by the "U" boat so maybe its some kind of "Karma" thing. !!! I only hope he flew better than he drove because according to the main dealer he had 3 front bumper skins replaced.
Regards John