dct mechatronics unit

[bmwfst1]

hi does anyone know where i can get a bmw dct mechatronics unit rebuilt?

[jcolley]

Originally Posted by bmwfst1

hi does anyone know where i can get a bmw dct mechatronics unit rebuilt?

Whats the problem with it? I rebuild the SMG hydraulic units from the ground up. I would be willing to look at it.

[bmwfst1]

well i have had transmission fault codes.
5a41 pressure sensor clutch 1 total failure
5a43 pressure sensor clutch 2 total failure
5a61 selector rod 1/3 fault
also sometimes the car shifts on its own even though its in manual mode

my car is a 2010 m3 and has 74xxx miles. i bought the car with 40,000.

according to the shop that read the codes i need new clutches, but the clutches dont slip at all no matter how hard i accelerate.

[jcolley]

the first two codes combined with the 3rd code would lead me to the wiring harness first. The pressure sensor codes are only generated when the signal returned from them in implausible, not when the actual pressure is out of range.

As the SMG3 ages, what we primarily see as causes of failure (aside from the silly brushed DC hydraulic pump motor) are wiring harness degradation on the hall sensor strips and the control wiring for the shift solenoid valves. Apparently, all BMW wiring insulation is crap, not just that inside of headlights and tail lights that have been recalled lately.

It would be worth a thorough inspection of the main wiring harness from the E-box down to the DCT, especially the large round barrel connector. These are usually where I see wiring problems start, either from the insulation nearest the connector pins, or an actual connector pin that was pushed back out of the shell when a transmission was removed for service.

The harness is available separately as well, item 2 here:
http://www.realoem.com/bmw/enUS/show...diagId=61_2289

I would almost guarantee it is electrical in nature give the symptoms you described.

[g2]

That's a great tip. Book marking this for future reference

[bmwfst1]

thanks for the tip im definitely going to have that checked out.

[deansbimmer]

I agree with Jay with the electrical suggestion. I have seen SMG and DCT transmissions both with wiring so brittle that the insulation was cracked and had fallen away enough for the wires to touch eachother if they moved just a little bit, especially on or near the transmission connectors. Your car is old enough that I would check that as a suspect.

[bmwfst1]

I had my dct removed a few weeks ago. Turns out there was a leak in the side pan. I had the harness replaced along with the filter. Also used about 7 liters of oil now the car drives great again. Thanks for everyone's input.

[Installsplus]

Originally Posted by bmwfst1

I had my dct removed a few weeks ago. Turns out there was a leak in the side pan. I had the harness replaced along with the filter. Also used about 7 liters of oil now the car drives great again. Thanks for everyone's input.

So in the pan how much oil was lost. Did u notice a leak in ur driveway ? I may have the same problem. U could be down a couple of litres and that would definitely cause shifting issues when under pressure.

[bmwfst1]

i didnt notice any leak in my driveway because the transmission is covered underneath. I think i was down two litres.

[Installsplus]

Originally Posted by bmwfst1

i didnt notice any leak in my driveway because the transmission is covered underneath. I think i was down two litres.

Thanks I will having it looked at next week.

[fedorlaszlo]

Hi guys,

You might know what to do...
I had 17 times in the computer the error code 5A5B - Control valve PV7: valve jammed. The car runs well, nothing to feel.
New mechatronics is needed, at least it was told to me at the workshop - without checking the car.

Do you have any experience/idea?

Thanks a lot!

[deansbimmer]

That's a rare failure. Not sure of the code details but fixing it will not be financially viable unless you know of a specialist that repairs these mechatronics units.

If it doesn't affect the driveability, you could keep driving it until the DCT fails altogether, then just replace the transmission. Or, replace it now if you don't want that hanging over your head.

[bmwfst1]

Check and make sure the two pans are not leaking before you spend any serious money.