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Discussion Starter · #1 ·
My driver side window motor toasted itself trying to move on a cold day. The car still started and drove, but fuse 10 had gone out. Servotronic malfunction error with heavy steering and no response from the window. Same issue as detailed a couple times before:



I replaced fuse 10 the same day which brought back normal steering, but the window motor was still gone with an anti-trap warning present. I drove the car like normal thinking I would order a new motor and drive it in the mean time. A few days later, the steering lock stuck (yellow icon) and the car would not start. Thinking it was a battery issue, I took the battery out of the car and charged it up at home. The next morning, the car started fine. Thinking my problems were solved, I turned it off after a few minutes and went inside. By lunch time, it was back to the no start condition.

At this point I had it towed to the local BMW dealer to check the codes. They refused to check and codes and just told me it needs a steering column replaced for $3800 CAD. Tried the battery charge trick a second time to no avail. Also tried unplugging IBS but that did not work either. In the mean time I ordered a new steering lock module and a window motor that I will have an indy mechanic put in, but I just have a hard time believing that the steering lock died after 16 years of service exactly two days after an electrical fault elsewhere in the car. Anything else I can try to get this back on the road quicker?
 

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The update was not clear enough it was best if you included the fault code figures, also the fault details. Do you mean CAS is not communicating or "certain control unit or ELV not supplied with terminal 15?.
I understand CAS is not communicating but many control unit include locking and unlocking the car will not be powered if CAS haven't supply terminal 15 to them, CAS itself doesn't need terminal 15 to be powered.

Check fuse F7 and F15.
 

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Discussion Starter · #4 ·
The dealership initially claimed they could not hook their computer up because the ignition could not be turned on. I argued with them that this was incorrect. They did hook their computer up and sent me the following:

"Here is the test plan we did this morning by connecting by VIN…it shows no communication at terminal 15 which is ignition. The column needs to be replaced to unlock the steering lock so ignition can be turned on for further diagnosis. Further than this I can’t tell you anything else as we need further diagnosis once the car is running."

I'm not sure I would put much stock in this, not sure that they even scanned codes.
Rectangle Font Parallel Engineering Schematic
Rectangle Font Parallel Engineering Diagram
 

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Check fuses above.
Still not enough data. CAS doesn't need ignition on to diagnose.
This issue needs more troubleshooting effort. Need the fault codes "fault page" and what control unit triggered them and the detail attached to each one when double clicked on.

Current will not be applied to steering lock if CAS was malfunctioned or no able to authenticate the release of the steering lock and will be a deadlocked. Is there a ELV fault code?.

You need first to verify CAS is powered, if powered then initial possibility CAS is faulty, if not powered may be there is a short in CAS circuit caused by the burnt F10 fuse, more troubleshooting is required.
 

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Discussion Starter · #6 ·
Update: there was corrosion in the passenger door which affected the comfort access module. This was causing the electrical issue. Unplugging it (and the driver's side so it doesn't happen later) solved the issue.
 

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Discussion Starter · #8 ·
A garage did this for me, but they said the passenger door comfort access was shorted. They unplugged comfort access connections in both doors and now it seems to be working fine.
 

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The issue is resolved by resetting CAS.

that's was the next step to advice IF you came back with feed back on verifying CAS supply fuses but you never did.

They said they found multiple K bus fault, you didn't mention any fault except CAS communication issue, were there other faults logged??, but this is matches my previous comment in my post "no short without fault code" this car is so sensitive to electrical performance, it does measure constant current draw, so any major short or defined as a short would draw current to cause continuous fault triggering for current draw and comfort access control units faults, this how the system works in this car, there is no way to misdiagnose excessive current draw, it will be logged and the owner will notice with simple scan and battery discharge caution on display.

Now they requested to replace the shorted door handle, did they replace it?. Door handle included in invoice price?.
 

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Discussion Starter · #12 ·
They quoted new door handles but I elected to leave the comfort access unplugged.

Unfortunately I can't answer your question about the faults because the BMW dealership refused to scan it. I assume that the door handle was throwing a fault code for the garage to figure it out.
 
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