£ C43 £ AMG £

Hello all and happy new year,

I have been viewing posts on this site for a few months, its a great site and very useful, so I have finally signed up and tried to help.

I don't want to cause alarm but I say BEWARE because my friend at an MB specialist has seen this problem and told me to check as worst case it damages the ECU which can also damage the gearbox.

The first time I looked was last week and that's probably the first time anyone's has looked....its a 1998 model which I have own for 6 months. In the passenger side foot well under the sound proofing material and underneath the alloy panel held on by three plastic 10mm nuts which on my car has a computer labelled by siemens (I think its the Gearbox ECU) and also a relay attached to the alloy panel.

I found oil on the wires and plug to the ECU and also about a table spoon amount in the foot well which I have all clean up. My question is how did it get there because I can not physically see oil along these wires to any point apart from near the ECU and would like to point out is up side down and means the oil is travelling up. THE OIL MUST BE TRAVELLING INSIDE THE WIRES UNDER PRESSURE? from the gearbox and will eventually get into the ECU. I have sealed the ECU up in a plastic bag around the wires and will check soon again if there is oil inside the bag and if there is no oil outside the bag then my theory is correct, although I may be wrong.

Has anyone experienced or checked it takes about a min to lift the carpet and undo the alloy panel?

MBHustla858

very common failiure w/ the electronic connector on the transmission. once the seals fail the fluid will travel all the way to the controller ultimatley killing it

MBHustla858

also to get that connector out it'll take a 7mm socket... i think its the only place you'll use a 7 on that car....

£ C43 £ AMG £

Thanks MBHustla858 sounds like a simple and cheap fix before it turns into exactly the opposite, I will check the connector on the transmission soon

£ C43 £ AMG £

just to also say that mercs in the U.k are limited in mods, I just managed to fit and source some 19" and the rest are personal touches. Whats wrong with the U.K a supercharger kit fitted is about £20000 thats 3 times the value of my car?


nothing to say for the germans apart from they make them and they do it well

Back2Benz

nice ride!...I love those wheels...now if I can just find a set in 17 or 18"s locally

silence

sc- is supposed to cost at least as much as my car did in the states as well.

how do i check for this problem?

MBHustla858

disconnect the electronic connector from the trans and if fluid comes out ur fuukkedd.... time for a new connector

StapleGun

Thanks for the 411 on this issue, will look into it...

£ C43 £ AMG £

Do you know where the connector is on the transmission please?

Asterisk

Yeah, this sounds like a good thing to check out. Is this a c43 issue only, or all w202 models?

tbenz

its the elect connector on the trans rt frt side,, this is a common issue with all the other models also ,with the 722.6 transmission,e class,mls slk,sl,c class,s class
if you get to it before the fluid gets into the ecu it will save you a lot of money, replace the connector and clean the connector with some elect cleaner

KJI3jflarryfe93

hey buddies, if i put the car on a hoist and stand under the car can this oil leak be spotted from down under looking at the trans?

can this bad rubber seal be changed outside the car disconecting the wires or must it be changed from inside the cabin>?

where does this oil come from?= if there is any leak then the cabin must smell like oil inside, mine does not do it yet!

cheers

£ C43 £ AMG £

Thanks tbenz I will be sure to check under the car and order the parts needed very soon.

To see if you have this problem you don't need to get under the car you only need to do this to fix the conector /seal is on the gearbox . Just look in the footwell location where you will find the gearbox ECU.............. THE OIL IS TRAVELLING INSIDE THE PLASTIC COVERING OF THE WIRES because the oil is under preassure from the gearbox where the seal has become weak. The harder you drive your car the more preassure will be created in the gearbox and the more oil will get through......... and also depending on how badly worn the seal is. This is simple fix but would probably cost around £3000 if oil gets into the ECU and then also damages the auto box.

KJI3jflarryfe93

hi to ya all, i dont get it, how the oil travels on the wires=? how does it come out from the transmission=? is it the ATF oil or what=? and how does it get inside the wire and travel the long way into the passenger footwell and then drains the gearbox ECU=?

MAY I GET A proper explanation please, of this crappy mercedes problem!

mercedes do they know anything about this problem>?

should i cover the ecu with a plastic bag or something?

thanx for the proper input. happy driving with all your c43s

tbenz

i`ll try to explain it the best i can, the connector on the transmission starts to leak trans fluid, at the connector the fluid gets pulled into the wiring by the flow of elect current and travels through the wiring to the components on that circuit the ecu is usually the first to start seeing the fluid, this is a slow process and happens over time

£ C43 £ AMG £

Sorry kowalski don't want you to get paranoid.

If you checked the ECU location behind the foot well ally plate and you have found there is no oil on the plug/wires on the ECU then don't worry, you don't need to replace the connector on the gearbox, becuase it has not gone weak I am just unlucky

As tbenz says its a slow process you and may find it takes many hours of driving for oil to work its way down the wiring loom toward the ECU.

Mine has done 100 000 miles...... but still quick as the wind though.

svt ricco

post some more pics of your ride. i don't think i've seen it in the picture thread. thanks

thegame11

is this still open because when my car got rain water from clogged rain drains I was drying the carpet and found oil right under the place where you guys r talking about but not any where close to the ecu. can some one help me if I post some pictures

nhmercracer

The transmission control unit (TCU) is attached to the metal plate under the carpet on the passengers side. The oil leaks from the transmission connector, and wicks up the wires to the TCU, eventually damaging it. The fix is to replace the connector sleeve, and dry the wiring harness. Ignoring this problem will cost you $$ later.

thegame11

ok I don't understand some are is the TCU that gets damaged some are saying is the ECU, are they the same thing. can someone please help me out because i found oil on the wires to the ecu too now. where is the rubber seal located on the transmission?

503C43 ////AMG

ECU is under the hood, the TCU is the one in the passenger foot well.

DRBC43AMG

Go read post #79 in this thread: https://mbworld.org/forums/c36-amg-c...ml#post4919922

thegame11

thank you DRBC43AMG now I don't know if our cars look similar underneath because I have a c280 inline 6 but here is a picture from my transmission is the connector the one circled in red. I can't tell from the pictures of the thread that you showed me and again thank you very much

DRBC43AMG

No, thats looks like the plug going into the passenger footwell. The dreaded plug is on the gearbox. Look at the other end of the cable and you will certainly find it.