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Old 8th August 2011, 16:05   #1
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Unhappy Need help - ECU failure?? in BMW 3 Series

hello experts!,
some background:
Car: 2007 E90 - 320i
Mileage: 38+K KMs

A few weeks ago I had left my car unused for a couple of days. when i cranked her she started up without any issue, i let it idle for a good minute and a half, stuck her into reverse - when i got the following errors and the engine cut itself off. i tried cranking again, but the car would just crank and not start up.
i turned off the ignition fully removed my key, then re-inserted and pushed start - viola! started up normally, and the errors were gone.

the car worked flawlessly for about a week after which it gave me the same 3 errors during a drive and cut off my engine again. I pulled over, did the switch off/on and drove off. emailed the pics of the errors and called the service station, he said since the error has disappeared it might not be serious and if i get the errors again, bring it in for diagnostics.

NEXT day on the drive to work, same errors, but this time the car just wont start- i have to tow her in to the service station.

the mech does a diagnostic and tells me that i need a new DME !!
is this right? i dont see how a 2007 car that has run under 40k KM can have issues with the main control module?!

everywhere i search indicate the errors are related to DSC.
if the DME itself is faulty, wont it be unable to produce errors?

anyways, i need advice whether it is really correct to change the DME - its costing me around 1 lac! is there anywhere else i can get a second opinion?

thanks!
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Need help - ECU failure?? in BMW 3 Series-img_0654.jpg  

Need help - ECU failure?? in BMW 3 Series-img_0655.jpg  

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Old 8th August 2011, 18:44   #2
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Default Re: Need help - ECU failure?? in BMW 3 Series

I'm not that knowledgeable about BMW's, but still going by common sense, check what exactly these tell tale lights are, and sort out those problems. I guess one of them is of tyre pressure. Get it sorted.

Also, try resetting these error codes and re-setting the DME from the A.S.C.

EDIT: Some pondering over the net, and it seems that '07 E90 320i's DME is known to fail, and while at it, the symptoms are exactly the same. The DME wrongly interprets sensors and hence throws error codes randomly. Some members can confirm.

Last edited by dhanushs : 8th August 2011 at 18:57.
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Old 8th August 2011, 19:04   #3
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Default Re: Need help - ECU failure?? in BMW 3 Series

I believe resetting the software might help. What did the service people say ? Did they try re-setting it ?

It's too early to change the DCM i believe with very few miles on it.
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Old 8th August 2011, 19:14   #4
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Default Re: Need help - ECU failure?? in BMW 3 Series

After a simple google search I am able to find out that bmw certainly has a problem with the dme. This is super sh** since I also own a 2010 320d and would hate this happen to me.

Now since dme is a critical component and requires coding stuff and importing it and doing a DIY doesnt seem reasonable.

You can try contacting BMWIN or else go the service centre way. This is why people dont buy Germans and we have the respect of owning one.
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Old 8th August 2011, 19:28   #5
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Default Re: Need help - ECU failure?? in BMW 3 Series

Quote:
Originally Posted by zeddo View Post
hello experts!,
some background:
Car: 2007 E90 - 320i
Mileage: 38+K KMs

A few weeks ago I had left my car unused for a couple of days. when i cranked her she started up without any issue, i let it idle for a good minute and a half, stuck her into reverse - when i got the following errors and the engine cut itself off. i tried cranking again, but the car would just crank and not start up.
i turned off the ignition fully removed my key, then re-inserted and pushed start - viola! started up normally, and the errors were gone.

the car worked flawlessly for about a week after which it gave me the same 3 errors during a drive and cut off my engine again. I pulled over, did the switch off/on and drove off. emailed the pics of the errors and called the service station, he said since the error has disappeared it might not be serious and if i get the errors again, bring it in for diagnostics.

NEXT day on the drive to work, same errors, but this time the car just wont start- i have to tow her in to the service station.

the mech does a diagnostic and tells me that i need a new DME !!
is this right? i dont see how a 2007 car that has run under 40k KM can have issues with the main control module?!

everywhere i search indicate the errors are related to DSC.
if the DME itself is faulty, wont it be unable to produce errors?

anyways, i need advice whether it is really correct to change the DME - its costing me around 1 lac! is there anywhere else i can get a second opinion?

thanks!
hi
i googled and found check this url
Pelican Technical Article: BMW DME Motronic ECU Swap / Repair
http://www.ehow.com/about_4691046_what-dme-relay.html
some time the relay also can be bad not the dme itself
so please check before trusting the authorised service centre and check for outside independent garage also
most mechanics give false excuse that sensor has failed etc
i my 10 years working as a electronic techincian i have seen only 1 or 2 sensors failed
please
check
narry

Last edited by narry : 8th August 2011 at 19:32.
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Old 8th August 2011, 19:28   #6
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Default Re: Need help - ECU failure?? in BMW 3 Series

Try out this link

ModuleMaster rebuilds ABS modules for as low as $100, 2 day average turn-around, 5 Year Guarantee

Hope it helps if you have reached the inevitable.
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Old 9th August 2011, 21:37   #7
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Default Re: Need help - ECU failure?? in BMW 3 Series

I have read about these guys a lot
Automotive ECU suppliers

Quote:
BMW that came in for repair would run fine for a while

But then stop completely for a few minutes before restarting and carrying on as if nothing had ever happened. The trouble with this sort of fault is that all the tuning and diagnostics in the world can't find it unless the fault occurs while the test gear is hooked up to it. I think it was Volkswagen who started the widely held belief that linking the car to a computer will fix everything, it won't,and it can't find a fault that is reading within its correct limits, but fortunately the fault did happen to us while we had the test gear attached. The cause was a greatly reduced ignition spark energy level.

The fault was caused by the Ignition Control which unfortunately is part of the Injection Control Unit and not available seperately. The price of this was bad news and strongly reinforced the owner's decision to go Diesel on his next purchase. Luckily though the unit had not damaged any unavailable parts within it though so a reconditioned unit cured the problem

Last edited by ajmat : 9th August 2011 at 21:44.
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Old 17th August 2011, 18:08   #8
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Default Re: Need help - ECU failure?? in BMW 3 Series

any update on this one? were you able to find a solution?
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Old 19th August 2011, 17:26   #9
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Smile Re: Need help - ECU failure?? in BMW 3 Series

Firstly I apologize for the delay in updating the thread. I had been scouting for answers all over the place, but in vain. All the links i could get online were out of the country.
I found only one place in Pune that was agreeing to 'look' at the problem and see if it was fixable. They had done some work on Merc/Audi ECUs in the past but not the particular 3 series I have so weren't sure of a sure solution. It would be only trial and error. Additionally, they would only let me know the cost of repair once they inspect the device - could range from 25-50k according to them.
In all probability, the ECU was dead anyways, so I thought why not go ahead with the attempt to repair. However, the BMW workshop people refused to disconnect and give me the ECU for repair, if I wanted it, i'd have to take the car away from them - this would mean hiring a flatbed and moving it across town, then possibly back again in case the repair attempt failed! Towing would cost me another 5k, at this stage I'm growing more and more frustrated with the increasing costs.

I try my best to crack the BMW guys, but they don't budge because of policy (which they explained to me) and i respect that. However 3 days ago I have a breakthrough & manage to convince them to let me have a look at the faulty DME myself and see if i can figure out if it can be repaired at all.
Having an electronics background, and having read about the possiblity of water damage, etc., I felt it would help to assess the extent of the damage and whether it would be worth the effort to move the car to the other garage.

So finally 2 days ago I got myself to the workshop and took a look at the part.

Need help - ECU failure?? in BMW 3 Series-img_0690.jpg

First look showed me telltale signs of water seepage and damage to the electronics was imminent:

Need help - ECU failure?? in BMW 3 Series-img_0681.jpg

Notice the corrosion on the bottom screws and cover plate, compared to the screws on the midsection and rest of the plate. The dotted line is up to where the texture/colour of the metal was different due to water damage.
Need help - ECU failure?? in BMW 3 Series-img_0682.jpg

Next I managed to get the lid open after wrestling with it (was stuck to the PCB with high quality silicon - so well that it bent the sheet metal!)
Once inside, this is what greeted me. You can clearly see the extent of corrosion - (the type that we see on batteries), but it is limited to the bottom part of the device (see dotted line)

I did also inspect the engine bay compartment where this is installed - it has a good drainage system and also the device itself rests about 2 inches above the bottom of the compartment, so I'm unsure how this kind of damage has occurred.
Need help - ECU failure?? in BMW 3 Series-img_0686.jpg

A closer view of the corrosion:
Need help - ECU failure?? in BMW 3 Series-img_0683.jpg

also affected some resistors+capacitors
Need help - ECU failure?? in BMW 3 Series-img_0685.jpg
and also an IC
Need help - ECU failure?? in BMW 3 Series-img_0684.jpg

anyways, Looking at it at this point of time, I'm like totally lost hope of any repair and ready to cough up the 90k for the new part, but a small engineer part of me still insisted that I should take a last chance and give it another shot.
Since the corrosive reside is a good electrical conductor, I figured it could probably be causing shorting between the IC and other parts hence causing wrong voltages to flow and generate the errors.
So I convince them (with my puppy face! lol) to let me clean up the part and see if it works, if it doesn't I'm ready to replace it anyways.
By now they have grown tired and empathetic of my situation, so they agree, but will not take any responsibility for further failures
I say OKEY DOKIE, just check if the car starts.

So that's what I eventually did - picked up some medical alcohol and a toothbrush, gave it a good cleaning, packed it up and had the technician connect it. One crank and the baby started purring like a little kitten!

They kept the car running for couple of hours to check if temp would cause any malfunction, it didn't. they cleared the existing errors and ran a diagnostic - results came out peachy!

I paid the towing charges, got into the car, drove home and shes running fine... since the last 24 hours at least!!

All in all ESTIMATED cost: 96,199/-
Actual cost: 3800/- for towing and diagnostics ++ some loose change for the alcohol and toothbrush!

but actual value is the experience gained!
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Old 19th August 2011, 17:36   #10
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Default Re: Need help - ECU failure?? in BMW 3 Series

@zeddo Oh my holy heavens!!! I wouldn't have dared to such a thing if I owned a BMW and had an electronics degree. Amazed to hear this and really happy for your ride!!! Here's wishing you many more happy miles!!

Just a few questions-
1) Did the mech guys ask you to bring it for a checkup of sorts after some time?
2) Now that you have "touched" the DME, what's the status of the warranty on that? You mentioned they won't take responsibility; does that mean warranty void?

:clap
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Old 19th August 2011, 17:47   #11
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Default Re: Need help - ECU failure?? in BMW 3 Series

Quote:
Originally Posted by zeddo View Post
but actual value is the experience gained!
zeddo -

OK, now we have all cleaned up the module, did you manage to find the source of the water damage?. I guess that's more important, to avoid failures in future. Specially because, I have read lot about E90 320i's DME's failing. May be the car has a default design problem, due to which water gets into the module?

I would suggest to sort that out too.
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Old 19th August 2011, 17:54   #12
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Default Re: Need help - ECU failure?? in BMW 3 Series

Quote:
Originally Posted by ssh1979 View Post
@zeddo Oh my holy heavens!!! I wouldn't have dared to such a thing if I owned a BMW and had an electronics degree. Amazed to hear this and really happy for your ride!!! Here's wishing you many more happy miles!!

Just a few questions-
1) Did the mech guys ask you to bring it for a checkup of sorts after some time?
2) Now that you have "touched" the DME, what's the status of the warranty on that? You mentioned they won't take responsibility; does that mean warranty void?

:clap
1) No. but they did scan it for any errors prior to me taking the car away.
2) my car is about 4 years old, so no warranty anyways! ( If it was in warranty they would have had to replace the part free & I wouldn't have had the pleasure of dissecting it right?!)

Quote:
Originally Posted by dhanushs View Post
zeddo -

OK, now we have all cleaned up the module, did you manage to find the source of the water damage?. I guess that's more important, to avoid failures in future. Specially because, I have read lot about E90 320i's DME's failing. May be the car has a default design problem, due to which water gets into the module?

I would suggest to sort that out too.
Yes, I will do this myself probably this weekend. I had asked them to seal the lid of the device using silicone sealant before finishing connections, but they refused citing that it may cause a ventilation problem guess i'll have to do this myself too!

Last edited by zeddo : 19th August 2011 at 17:57.
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Old 19th August 2011, 18:04   #13
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Default Re: Need help - ECU failure?? in BMW 3 Series

Quote:
Originally Posted by zeddo View Post
2) my car is about 4 years old, so no warranty anyways! ( If it was in warranty they would have had to replace the part free & I wouldn't have had the pleasure of dissecting it right?!)
sorry didn't remember that!
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Old 19th August 2011, 18:07   #14
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Default Re: Need help - ECU failure?? in BMW 3 Series

this was a nice DIY. i had repaired couple of my handsets in such a way. but now i think its not possible to seal the cover properly. i would say its better to go for a custom plastic or metal box with inverted slant holes so that moisture or water doesnt seep in.
also i dont remember the name of the paste but its used to safeguard electronic boards and circuits.

its no conductive but is a bit oily. it prevents corrosion. try to apply that over the pcb circuit too.

great man you saved 1 lac , that too would have gone waste due to faulty packaging from BMW.
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Old 19th August 2011, 19:00   #15
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Default Re: Need help - ECU failure?? in BMW 3 Series

Spray WD40 around the ECU area
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