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Discussion Starter #1
Hi guys,
I'm going to reach out to all of you in hope to get a little help with my problem!

So my dealer (and best friend) was driving my M6 and he forgot that the smg don't really like downshifting from 2 to 1st at slow speeds, so unfortuneatly he did..
My transmission still drives as it should, No changes in the shifting between gears when driving. But now it has troubles when I come to a stop and need to reverse, everytime I need to go into N, the red cog comes up on the dash. I can then turn off the car and then go into reverse. The same thing happens when I then go into N again wanting to go into 1st, I then need to turn off the car to do that..
Do you have any idea what is causing this?
I have great skills with motors and many years ofe experience, but I cant seem to find the root of this problem..


All the best
Martin Tandrup, DK
 

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Interesting, never heard of these issues before. Knowing what codes popped up would help. Seems like shutting off the car resets the error which allows you to get back into gear. Perhaps re-adapting the trans could help but that could also cause the car to not be movable if you don’t succeed in the re-adapt process.
 

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Discussion Starter #3
Thanks for your answer!
Yeah maybe I just need to do the adaptions, but the reason why I haven't done that procedure yet is, as you say, if it fails it can't move 🤥
It's in a warm garage for the winther, so it wouldn't be a problem but I hoped we could kind of close in the possible causes here with you guys 🙏🏽
 

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If you post up your codes we can take a look. I presume you have INPA or ISTA? I also have an idea that is a reasonable backup plan also, after having dealt with adaption silliness several months back. Also there are more people on the M5 side so you may get more input over there.
 

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Whatever it is, your friend shifting from 2 to 1 had nothing to do with it. With the info provided it's nothing but guesses, mine is the gps wiring.
 

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There are 4 shift range solenoids on the top of the transmission. One is responsible for ****s between 1st and reverse. I would also check that valve and the SMG wiring harness that controls it. The wiring harness has been known to get brittle and fail. Hopefully the fault codes will pinpoint the cause. good luck
 

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Discussion Starter #7
The codes yeah, sorry I forgot them! 🤦🏼‍♂️
I use ista, the codes I get is:
ECU
4F40
4FA0
4F43
4F42

SMG
2810
2857
 

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Seems the SMG pump motor is week. Delete the faults Monitor the SMG pump pressure while shift as you mentioned and you should see the pressure drops below 50 bar and red COG appear. With ISTA do the accumulator test.
 

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Discussion Starter #9
I have done the accumulator test, several times, and it's good No faults on the accumulator..

I have also changed the smg motor, so that's brand new! Could it be something about the bleeding procedure and the adaptions together with the new motor?
 

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Double click on each fault and print screen and post here so I can see what is the conditions and values when the problem occurred, I need to know what is the pressure and voltage when this happens.

I am assuming that the car in a normal configuration when I diagnose, but if you opened the hydraulic system and change the SMG pump motor, then you need to do the clutch valve and block bleeding several time (5 times and more) top off the SMG oil (this is very important, the excess will be leaked down, clean and continue and top off again). Use a battery charger when you do the bleeding.
Make sure the battery is good and charged when you test.
 

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top off the SMG oil (this is very important, the excess will be leaked down, clean and continue and top off again).
Errr... no. Read TIS. Fluid is only to be checked when depressurized. Else you'll overfill and make the mess you're describing.
 

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4F40 and 4FA0 usually go away with a new SMG motor. Are they current faults or ones stat are still stored in the memory. You might have the typical issues with insulation deterioration on the wires from the gear position sensor (GPS) in addition to pressure leaks at some of the solenoid valves.

Something that can help mitigate the risk of a failed adaptation is to buy another used SMG module, and use that one as the controller that you perform the adaptions on. I ended up going that with my other spare controller. I keep that in the trunk for emergencies. The only risk with this approach is that the used one that you get was defective in the first place, that has happened to a few ppl here. You don’t have to worry about rewriting the VIN on the module since the car doesn’t care.

If you are a hardware guy, you could also attempt to dump the EEPROM off the module and achieve it on your computer so you can rewrite it but I don’t think anyone has actually bothered to attempt that and I don’t think you can easily over the OBD connection without some special tools.
 

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All four 4Fxx codes are smg pump motor related.

And yes the SMG flash has been downloaded and some effort to tweak was made. I can't find the username thought it was Ferris.
 

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Discussion Starter #15
I've done the clutch slave bleeding 5-6 times, but not the Block bleeding, that might be my failing step?
Is it correct that I've to loosen up the bottom bolt on the block itself when I'm doing the block bleeding?
 

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I will ask Ferris, but he’s a hardware and software guy. I wouldn’t be surprised if he tapped in to the microprocessor. But what I understood was that SMG tweak efforts were more focused on altering the maps, which reside in the DME. It seems the adaptations are in the SMG controller along with the program. Also I know ppl have compared the 0da from the Euro and US SMG cal, but that doesn’t have contain the memory for the adaptations.

For sits and giggles, I first hooked up the SMG module from a different car and it started but didn’t shift. It felt like the clutch was also not fully engaging also, but surprised it worked, I then adapted it. I see the hex values for the adaptation change.

What we need is a tool like terra’s MSS6x flasher which can dump the whole bin and rewrite. That would totally remove the risk of unable to recover from failed adaptations.
 

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It’s best to bleed the slave a few times then the upper block a few times. Then slave then block. This will take like 1hr so make sure you have a separate power supply that can deliver 20-30 amps at 13v, not a small battery charger like a CTEK.

Absolutely do not try to do adaptations on a weak or low voltage, because the adaptations is measuring current flow at the solenoids and calibrating mechanical or sensor contact, if you have low voltage, that can cause a skewed current measurement.

You shouldn’t have to touch the bottom drain plug, but I’m assuming the motor (and pump) were removed earlier and this is not the first time running it after the hydraulics were opened.
 

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The drain plug holds in the pressure relief cartridge. If the drain plug is not secured, fluid will squirt out I’m under high pressure when the pump runs. If it’s totally out, when the pump runs, no pressure will build up at all. The only reason to run it with the pump on is to flush the system, but it really only flushes the circuit in the block itself and none of the other parts.
 

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So these are active codes you see now or are they from earlier? I’m on my phone so I can only rely on my own rusty translations, but it were in English it would still be cryptic. The measured values from when the 42 and 43 codes were set show 3bar. That’s really low, the 40 and A0 codes show 30 bar, also low. I’d do the bleeding cycle a few times. Then run the engine (make sure you have plenty of fresh air ventilation so you don’t get CO poisoning) or with the power supply running have the car in the on position but engine off and view the system pressure live in INPA. It seems like your pump will turn on and off a lot because you seem to be getting low pressure. You may want to record the screen with the pressure read out so you can see how quickly it is bleeding off.
 
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