transmission control module

[mickmjl]

hi all i strongly suspect my tcm on my 170 slk is faulty .can you simply plug in a replacement one or is it more complicated than that ie has to be coded by mb etc.thanks for looking.

 

[brandwooddixon]

I guess people will want to know the model year or gearbox type.
In any case any independent that has online access to the MB servicing network and STAR should be able to code it to your car if that's what is required.

 

[LostKiwi]

That will be a 722.6 5 speed.

If you can find one from the exact same gearbox (the 722.6xx numbers must match exactly) it should be plug and play.

What symptoms are you seeing? In general the TCM is pretty reliable unless it gets full of oil.

 

[mickmjl]

it keeps losing all drive ie stuck in neutral . problem is i cant get it to a dealer or indie because it wont go.Ive tested the harness connections to the gearbox and they are good.just wanted to make sure the tcm is good before i assume its a mechanical fault and remove the gearbox and take it to a specialist to be reconditioned etc. theres no oil in the unit and the car is one owner apart from me with fsh.

 

[LostKiwi]

What does it show on the dash display?
Does it show D or R?

If so have you checked the gearbox oil level? Low oil will cause no drive.

 

[mickmjl]

the dash display is correect it shows p n d and r when it should.it doesnt go in to limp mode at all,just nothing straight away.what effect would to much atf have?

 

[LostKiwi]

Too much causes the oil to froth reducing pressure.
Too little and it can't get enough to maintain oil pressure.

 

[mickmjl]

thankyou lost kiwi for your time.i will check again the fluid level,but i do find that the dip stick is a bit hit and miss as having a plastic tip on it it doesnt seem to bottom out correctly giving me different readings which is not good being as how crucial it is to have the right amount in.

 

[alexanderfoti]

Yes double check the level

Be gentle with the dipstick, if you push it too hard it will bend in the bottom of the box giving an incorrect reading. You will feel when it touches the bottom.