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Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #

Posted by Chris Angus on March 16, 2011, 12:54 pm

Year of Manufacture *: ??

Hi, don't usually get involved with auto transmission, but thought I would take a look.
Now I need help. fault code P2502 gear implausable or transmission slipping.
Can anyone offer any guidance on testing these?

WDB2084482T139651

Chris

Re: Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #

Posted by Paul Howd <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT5151' width='330' height='300' border=0 style='border:none;'> on March 16, 2011, 8:46 pm, in reply to "Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #"
Paul Howd

I dont really have anything to do with transmissions either.

However...

In my somewhat limited experiance I tend to look for mechanical problems first.

What are the actual symptoms? What is the fluid like? What is the milage? If the fluid is black and smelly. I would drop the transmission fluid/sump and see if it is full of little black bits before looking at anything else.

Re: Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #

Posted by markcollins <iframe src='https://members4.boardhost.com/ukautotalk/info/user=ukat3069' width='330' height='300' border=0 style='border:none;'> on March 17, 2011, 9:18 pm, in reply to "Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #"
Mark Collins

HI Chris,
You need someone with star diag to check the gearbox data,not sure of your location? I am in Hampshire if you are near by I can check it for you,But start with the oil level checked at 80degrees with a workshop dip stick which you can buy from mercedes for £30.
mark..

Re: Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #

Posted by Paul Mathers <iframe src='https://members4.boardhost.com/ukautotalk/info/user=ukat3253' width='330' height='300' border=0 style='border:none;'> on March 21, 2011, 6:55 pm, in reply to "Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #"
Paul Mather

The clue is in the DTC translation, quite simply the TCM "knows" the ratio of every gear and can monitor them by a simple input vs output speed signal comparison, so a failure by the gearbox to achieve and then maintain an expected ratio will set this code. The only time this code can be caused by a control system fault is if the final drive ratio's been altered, ie; a diff swap or conceivably a mismatch in the TCM/ ESP/ABS module coding ie; wrong module(s) installed.

The only realistic external check available is the fluid level, low fluid = low hydraulic pressure = clutch and brake slip, note that the fluid level on these is checked with the engine running! If that's ok then it's fair to assume that the box has an internal component failure and needs a stripdown to to assess it further. HTH.

Re: Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #

Posted by Mark Carter <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on March 21, 2011, 7:36 pm, in reply to "Re: Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #"
Mark Carter

Do these suffer from the oil cooler issues that other merc's suffer from ?

It may be worth while carrying out a glycol test of the auto box oil. HTH

Regards Mark

Modern cars, Its all wizardry and witchcraft

Re: Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #

Posted by Chris Angus <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT5111' width='330' height='300' border=0 style='border:none;'> on March 22, 2011, 2:16 pm, in reply to "Mercedes Benz CLK230 - Auto transmission fault, fault code P2502 #"

Hi all, thanks for the replies. I couldn't confirm oil level as our dipstick had gone walkies, live data looked fine with regards to the speed sensors. found an old speedo cable in the end and measured oil level, which was very low. Was a trade customer so he took it away to fill, just waiting to hear back.

Chris

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