Transmission Malfunction Message (Includes Video)

[monto]

I was able to get a friend's cousin to run the error code after clearing all faults and making the problem take place while on the highway.

0X4F83 (20355) transmission monitoring coupling C >invalid signal

Anyone have any additional information related to this code? The transmission goes into safe mode while downshifting out of 6th gear.

Thanks for all of the help so far.

Cheers,
monto

[m34vert]

Slightly related but rather then dredge up an older thread or start a new one this may be the right place to start.

I have an '08 e70 that just started leaving stains in the garage. Dealership looked at it looks to be the valve body seal is leaking. It's a CPO vehicle so I don't know what the first 42k of it's life was like but I'm appalled that I'm replacing seals at 50k. Has anyone else had a similar instance? I didn't see any on a search other than for the e53's.

[monto]

Originally Posted by m34vert

Slightly related but rather then dredge up an older thread or start a new one this may be the right place to start.

I have an '08 e70 that just started leaving stains in the garage. Dealership looked at it looks to be the valve body seal is leaking. It's a CPO vehicle so I don't know what the first 42k of it's life was like but I'm appalled that I'm replacing seals at 50k. Has anyone else had a similar instance? I didn't see any on a search other than for the e53's.

After doing quite a bit of reading on my issues I came across the following forum posting which discusses a leaking sleeve connecting to the mechatronics unit.

http://www.bimmerfest.com/forums/arc.../t-401524.html

With respect to my slipping transmission an independent shop has recommended I replace the mechatronics unit. From the link above it appears as though many others have had good luck when changing the mechatronics albeit with different symptoms. Since the dealer recommended I replace the entire transmission at a cost of $7,800 I asked that they open a PUMA case to see if BMW NA is aware of any similar issues and if they can confirm this should resolve the issue. Any comments on the likelihood of the mechatronics being the culprit?

TIA,
monto

[Incubus]

Hello, been here for a long time now looking for a solution to this problem. But mine occurs whenever I start the engine. I was suggested by the dealer to replace mechotronik unit which is over 3 000$ for my tranny (4.8i). Have you tried replacing MAF?

[autoque]

Originally Posted by Incubus

Hello, been here for a long time now looking for a solution to this problem.

Which, the leaking or the malfunction message?

[Incubus]

Transmission Faulty message. There was a post right above mine, but it has been moved or smth. Today the fault has not shown itself but when i start the engine at times it feels like i've been rear-ended, though the car is in Park. Diagnostics reveal that the trouble is caused by mechatronik unit, but I just don't want to believe this. there must that can be done to solve it by not paying 3000 $ for it. When the fault message is not poping up the car goes perfectly. When it does - the tranny won't shift up until restarted. Only happens when i start the car, never in motion

[Incubus]

By the way - it had started just when I repaired sleeve leak problem, the morning after. It was done by some indy shop specialized in that.

[ard]

The mechantronics unit is also called the 'valve body'...

A classic failure mode with automatic transmissions is failure to maintain fluid- fluid gets hot, begins to break down, BMW stupidly says "lifetime", wear particulates build up, wear increases...unitl a bit of something gets stuck in one of the small orificies in the valve body, or against a plunger, and the tranny is 'stuck'...a particular gear or function does not work- can happen in a bunch of locations, each with a separate symptom. Sometimes there is a bit of crap that floats around in a limited area- tranny works fine most of the time, but then when the part moves it can show a failure. (an additional failure mode is tranny and fluid gets hot, seals heat, shrink, degrade...hydraulic circuits cannot hold pressure, shifting pressures degrade, wear accelerates....this is much worse, as a rebuild is required. The symptoms of this are more 'continuous', and are worse when warm.)

If I was having issues like this, I'd try a few things. (And I KNOW this is absolute heresy on these BMW forums) and not necessarily in this order.

1. Complete and thorough flush of the transmission. Potentially reverse flow, with solvents.

2, Remove mechatronics, clean/flush.

I'd only consider this when the next step is replacing parts. Not much to lose.

GL

A

[monto]

Awesome info!

Is there a separate procedure to flush the mechatronics unit specifically or just as part of the transmission?

Is there any way to test the mechatronics if you were to pull it out?

Thanks again,
monto

[ard]

I don't know on both counts.

I suspect the factory has a testbench for testing it, as would a rebuild facility.... just from a macro view, there is probably not a 'need' for ZF to publish/make a test procedure- they are in the rebuilding biz.

What is the labor you are being quoted for swapping the mechatronic? Seems like 2 hours based on looking at the procedure. Close?