darkone

Hello!

I am a new owner of a 2008 E60(m5) and have been seeing some interesting electrical issues with my car. Since it is out of warranty, I figured I would take a crack as fixing what I can myself.

On to the description of how the problem presents. I hope to make this detailed enough so that if anyone else is seeing the same behavior they will be able to find this thread and not have to jump through all the hoops I feel I'm about have too.

Occasionally going down the road over the past 2 weeks I have seen the ABS warning in the Idrive screen come up to warn me about driving carefully. but it would only show up for about 5-10 seconds and then go away.

So searching these forums I found out how to tell the age of the battery(stamped on the negative post of the battery) and found that it was the original battery that came with the car, 5 years old. So In Florida, we are lucky to get 3 years out of most batteries, so I bit the bullet and bought a new battery and had my local Indy shop re-register the battery.

So I drove the car back and forth to work for a few days and didn't see anything come up. However, yesterday I saw the same ABS warning as before and it went away. So this morning I hooked up my bavarian technic cable and cleared the codes, and took it out to run some errands around town. After fueling it back up, and only a couple of miles from my house all hell broke loose on the dash and I-drive. The ABS light came on, servotronic errors, brake warning lights, and the steering became stiff (like the power steering went out) and finally the Idrive screen itself went out and came back on repeatedly.

So I pulled over and shut the car off, and then started it right back up. and he steering came back and no errors.

when I got home I immediately pulled the codes. (It may be worth noting that when pulling the codes the ABS warning lights came back for a few seconds).

Here are the codes:

Engine module for S85

Current Fault Codes
2AFE:
Voltage at terminal 87
Error will not cause a warning light
Error is not currently present
Test conditions have been completed
Short circuit or signal interruption


Dynamic stability control DSC 87

Current Fault Codes
5DF7:
DSC: System voltage too high
Error will cause a warning light
Error is not currently present
Test conditions have been completed


Sequential Manual Gearshift (SMG_60)

Current Fault Codes
520B:
SMG: signal, lateral acceleration, is faulty
Error will not cause a warning light
Error is not currently present
Test conditions have been completed


5403:
SMG: Selector lever, LED R
Error will not cause a warning light
Error is not currently present
Test conditions have been completed
Signal or value below threshold


5201:
SMG: Signal, wheel speed, rear left, is faulty (DSC)
Error will not cause a warning light
Error is not currently present
Test conditions have been completed


5202:
SMG: Signal, wheel speed, rear right, is faulty (DSC)
Error will not cause a warning light
Error is not currently present
Test conditions have been completed


5203:
SMG: Signal, wheel speed, front left, is faulty (DSC)
Error will not cause a warning light
Error is not currently present
Test conditions have been completed


5204:
SMG: Signal, wheel speed, front right, is faulty (DSC)
Error will not cause a warning light
Error is not currently present
Test conditions have been completed


5103:
SMG: Supply voltage, transmission control
Error will not cause a warning light
Error is not currently present
Test conditions have been completed
Short circuit or signal interruption


Head-up-display (HUD)

Current Fault Codes
A4EB:
Power supply voltage, overvoltage or undervoltage
Error will not cause a warning light
Error is not currently present
Test conditions have been completed
Short circuit or signal interruption


Body Gateway Module (KGM)

Current Fault Codes
93BD:
Servotronik: Speed invalid
Error will not cause a warning light
Error is not currently present
Test conditions have been completed
Short circuit or signal interruption

So other forums threads in various places have suggested based on some of these symptoms that it could be the IBS, or the alternator, or the voltage regulator module.

The new one that caught my attention today was this one:
5DF7:
DSC: System voltage too high

I assume that the alternator must be a PITA to take out on this car which would need to be done for either the alternator replacement or the voltage regular replacement. And I think I may be able to unplug the IBS from the battery to see if that is causing these issues.

I'm guessing that over or under voltage would cause these kind of errors as I have never seen ALL 4 wheel speed sensors going bad. I have looked up all the codes posted here and this is my best guestimation so far as to what is happening. I have sent the same codes to my local shop and will see what they suggest.

If anyone has seen this before and can give some advise it is appreciated.

Thanks!

darkone

Update: I took the car to my local Indy shop and for 2 hours of shop time, they hooked my alternator up to a oscilloscope and found that the alternator was not producing the right voltage at around 3k RPMs. So I have them scheduled to replace it this week. Hopefully they figured out this intermittent issue correctly!

H F

These cars are really power hungry. as soon as the alternator looses the ability to maintain the correct voltage . The electrical sytems on these cars are very sophiticated. and really sensitive to low voltage.and will send error msgs.. You should b back in the race with the new alternator...I woild also change the charging relay in the trunk fuse box as well

AchtungE60

I was going to suggest alternator. All of those modules have 2 things in common. Voltage issues. Battery is good so alternator is not steady.
One should clean his engine every 4 months or so with degreaser and make sure that alternator is his in the process. Rinse it all off well. Helps to keep things clean and keeps an eye out for leaks.

Forest Ngo

can you confirm that fixing the alternator has fixed this problem and so far does not see the error codes come back?