[dan.trainor]

@platii can you please help me clarify?

I went through the list and found:

• 12.6V between 16/47 (GND) and 17 (Supply )
• 0V between 16/47 and 29 (wake-up)

I'm confused on:

Line CAS_ELV+ between M137a electrical steering column lock and A149a Car Access System

There are two ELV lines between these, neither of which describe negative nor positive of themselves, unless I'm reading this wrong:

Is this a continuity test between 23/2 CAS/wheel lock and 24/4 CAS/wheel lock, respectively?

I'm still trying to find the ground support point - specifically the one mentioned here - I'll follow up with that when I do.

I'm starting to think this is a weak battery. Some of the other modules are failing during a vehicle test seemingly at random. It's worth noting that these tests described above were with a 2 amp AGM charger hooked up to the lugs under the hood. I ran the charger on the lowest power mode a few days back, and find that the battery appears to once again be weak. I had ran the described tests earlier and read 12.2V. I'm not sure which method of test this charger uses to indicate a battery charge % but just a few days later it was reading less than 10% charge.

I'm in no hurry. Good learning experience either way. Thanks for your feedback.

 

[platii]

I tried to find a diagram but couldn't as TISinfo is shut down.
I got some info when I was troubleshooting my SZL module failure.
Let me clear things up.
For ISTA to detect the DSC is has to be powered, awake, and online on the PTCAN-bus.
Fuses (specific for the M5):
1- Fuse F66 5A Terminal 30G up to 8/2005 RED/BLACK wire connected to pin 17 at the DSC.
OR
1- Fuse F78 5A Terminal 30G from 9/2005 RED/BLACK wire connected to pin 17 at the DSC.
2- Fuse F1 50A Terminal 30 RED/YELLOW wire connected to pin 1 at the DSC.
3- Fuse F25 25A Terminal 30 RED/GRAY wire connected to pin 32 at the DSC.
Ground:
1- BROWN wire connected to pin 16 at the DSC.
2- BROWN wire connected to pin 47 at the DSC.
WAKUP Terminal 15 (specific for the M5):
1- RED/GREEN wire connected to pin 29 at the DSC. This wire also connected to CAS wakup signal wire pin 19 RED/GREEN wire and they meet up at a junction bus inside the glove box. It may not get the signal from the CAS directly on the E60 M5 but it does on the E60. The importance here is you get the signal when you put ignition on.
PTCAN-bus (specific for the M5):
1- PT-can low signal RED wire connected to pin 15 at the DSC.
2- PT-can high signal BLUE/RED wire connected to pin 30 at the DSC.
For connection with SZL module through FCAN-bus (specific for the M5):
1- F-can low signal WHITE wire connected to pin 26 at the DSC.
1- F-can high signal BLUE/WHITE wire connected to pin 11 at the DSC.
Note: put the ignition on for diagnostic.
When you put ignition on, do you see the DSC and ABS lights on the cluster?
From the faults codes page on ISTA in the lower right press on calculate test plan and from next page see if you could see the DSC fault highlight it and click display and follow the instruction for troubleshooting. We need to verify the control unit is not completely dead.

 

[platii]

Sorry didn't see your last post, I am reviewing it now.
Is the above troubleshooting test plan from your car?

 

[dan.trainor]

I'm not able to KOEO right now, Best I can do is KO but I don't want to turn it over. There are no ABS or DSC errors seen from inside the vehicle itself. Once in a blue moon one would pop up about ABS, DSC, parking assist, blah blah, but generally a poweroff/on makes them go away. Figured that was caused by a misbehaving voltage regulator or alternator based on research I was doing, once in a while other systems behaved the same way. I'm not sure it matters since the engine hasn't yet been turned over but, part of this work effort involved replacing the voltage regulator on the alternator, too.

The Procedure I listed a screen shot of came from the calculated test plan. I tested supply voltage and wake-up open circuit. I have not gone through all these fuses you had listed. Where did you find the list of specific fuses? If I could have found such a comprehensive list of specific fuses then I certainly would have tested all of them involved, too.

 

[platii]

You should test each ground and supply wires individually against good known ground or power, don't test against each other.
The lights I asked about is the yellow light that should come up on the instrument cluster when you put ignition on ( means first start button push not to turn over the engine with a second push) not messages on the infotainment screen on the center console. If you don't see those yellow lights then the DSC control module either dead, not powered or grounded, or not woke up, or the signal of the ELV-cas is missing troubleshooting states, or not online on the can-bus.
Work in sequence as the troubleshooting.
Let us know where you start to have problems.

Is this a continuity test between 23/2 CAS/wheel lock and 24/4 CAS/wheel lock, respectively?

The answer is no or yes, generally the answer is no, they are 2 different ECU pins, but if under some condition they share a signal then the answer is yes. I can't help in this because I can't see the other wiring diagram or how the ELV is connected but they seem both are power.

I'm starting to think this is a weak battery

Not here where you have totally offline ECU with red color on ISTA, but generally yes this car required a charger during a troubleshooting because power gets low very fast.

Where did you find the list of specific fuses? If I could have found such a comprehensive list of specific fuses then I certainly would have tested all of them involved, too.

I have them written 2 months ago when I was troubleshooting my SZL malfunction as SZL communication is done through the DSC ECU.
The other fuses may be used to run the ABS motor. I listed them if you want to use them later, another thing is you may try to pull them off and check if the DSC gets back online with ISTA, if they inadvertently has a bad effect, this type of isolation.

 

[platii]

If I could have found such a comprehensive list of specific fuses then I certainly would have tested all of them involved, too.

Try to dig in ISTA I am sure you will find the diagrams that was on TISinfo, may be not easy accessible well connected to each other but that's the only way for now.

 

[dan.trainor]

You should test each ground and supply wires individually against good known ground or power, don't test against each other.
The lights I asked about is the yellow light that should come up on the instrument cluster when you put ignition on ( means first start button push not to turn over the engine with a second push) not messages on the infotainment screen on the center console. If you don't see those yellow lights then the DSC control module either dead, not powered or grounded, or not woke up, or the signal of the ELV-cas is missing troubleshooting states, or not online on the can-bus.
Work in sequence as the troubleshooting.
Let us know where you start to have problems.

Cool, I'll go through that again starting from the top keeping this sequence in mind. I've been trying to do this "by the book" in terms of what ISTA+ recommends, every step of the way.

The answer is no or yes, generally the answer is no, they are 2 different ECU pins, but if under some condition they share a signal then the answer is yes. I can't help in this because I can't see the other wiring diagram or how the ELV is connected but they seem both are power.

Noted. I interpreted the instructions as how to check for proper power at the end of the harness that goes in to the DSC unit.

Not here where you have totally offline ECU with red color on ISTA, but generally yes this car required a charger during a troubleshooting because power gets low very fast.

Right. Leaving in troubleshooting mode with the K-DCAN cable plugged in overnight will make the battery sad. Ask me how I know.

I have them written 2 months ago when I was troubleshooting my SZL malfunction as SZL communication is done through the DSC ECU.
The other fuses may be used to run the ABS motor. I listed them if you want to use them later, another thing is you may try to pull them off and check if the DSC gets back online with ISTA, if they inadvertently has a bad effect, this type of isolation.

Thanks for the feedback. I'll check TIS again and make a list of all fuses that might be involved according to the wiring diagram and see if I come up with the same list.

RE: SZL, I had an error two years ago, replaced the sensor, and that's been great ever since. After clearing codes and giving the battery another proper charge, the SZL error went away. Even when it was present, I figured the setting was lost due to the battery being disconnected from some months. It's been my experience that this will clear anyway, once the vehicle is on the ground and going lock to lock, with or without a calibration.

 

[platii]

I've been trying to do this "by the book" in terms of what ISTA+ recommends, every step of the way.

Yes this is what I mean by going in sequence as ISTA states.
1- Ground. pins 16 and 47.
2- Supply pin 17.
3- Wake up signal. You can verify voltage with ignition off/on does change.
4- CAS-ELV+. I think this is a continuity testing. CAS pin 23 to ELV+ pin 2, I think this is power line. and pin ELV- pin 3 to CAS pin 24 is ground, test both continuity to CAS just in case while you are in the area, you can verify by testing ELV pin 2 to ground and see if you got +12V and vice versa.
5- PT-CAN bus. I don't think you have a problem with the bus itself, ISTA will report it, other than the wiring is connected to the control unit. The wires should run to the KGM at the glove box.
Don't worry about the SZL, it won't communicate until DSC is back online.
Report back which steps checked OK.

Edit: Pins numbers

 

[dan.trainor]

While I wait until I get a chance to test further, a few questions - sorry if they're elementary. Figured I'd turn this in to a learning opportunity:

1. Known ground/supply, ultimately should I be using something right off of the battery terminals or are there better, fused, test terminals that should be used for this kind of diagnostic?
2. What does LEV actually stand for?
3. How were you able to infer which was CAS_ELV+ and which was CAS_ELV- (specifically, - and +)?

 

[dan.trainor]

Nice doc on ground points

https://5series.net/forums/attachments/e60-discussion-2/147571d1426694953-e60-start-problem-rough-idling-bmw-voltage-supply-bus-systems.pdf

 

[platii]

Only basic testing I use test light or a multimeter, engine bay has +12V battery pole and multiple chassis ground you can use.
ELV is Electric Steering Lock, you can find it with CAS under the steering wheel area.
As in the documentation terminal 30 is power so the other one is ground.
some documentation has info is not applicable on the M5.

 

[dan.trainor]

Ground, supply, and wake-up are ok, tested against known working points - positive and negative engine bay charging terminal blocks. However... that's erroneous if the chassis ground strap is not good. I'll test again tomorrow running a jumper cable from battery negative to engine bay ground post and re-test.

I got the kick board removed to test ELV voltage and/or continuity but it was gym day today and, well, I don't have the flexibility I need to do a back stand to access the harnesses. I'll double-check the pins of the harness according to the wiring diagram. I need to review anyway to figure out which are positive, negative. That wasn't immediately clear from the wiring diagram, unless it's supposed to be interpreted inside-out top-down where out/down is always the ground (e.g. diagram shows CAS -> ELV -> GND).

Thanks again for your help. Learning a lot.

 

[platii]

Easy to confirm if that ground used is good or not by testing it against the positive pole in the engine bay, no need to get a wire from the battery. When you get to the ELV you can confirm that pin 2 is power by testing it against pin 3 or any close by known good ground, again I think what ISTA required is pin 2 has continuity to CAS pin 23, to add up on that pin 3 is connected to pin 24, I think this will be checked OK, and you be moving to the next step checking PTcan-bus step, before that you need to check the DSC connector and pins are clean and no corrosion or deposits prevent connection or broken pins. I am not sure how you are going to tackle this last step the easiest way, the only thing I can tell you from my past experience on DSC-SZL research is on the E60 there are 2 terminating resistors on the PTcan-bus, 1 in the KGM and 1 in the DSC control unit. The thing that is confusing me is why there is no error for PTcan-bus, that would leave us with just DSC control unit internal failure, but for learning experience you can explore the PTcan-bus testing and feed back with the procedures and steps taken. Good Luck.

 

[platii]

at post #48 I mistyped the pin number for -ELV

 

[dan.trainor]

My point was that if I did have a chassis ground problem from the steel body to the aluminum front end via ground strap then the negative post under the hood would remain suspect. Anything I would test off of that would be erroneous.

But to your point even with the assumption that same post does provide a good ground, I see +12.6VDC between testing with that ground post, the adjacent supply post, and supply/ground pins of the DSC harness, which is healthy.

The DSC harness and connector pass an initial visual inspection but that doesn't confirm that the internals of the harness, to include the conductive receiving pins themselves or even the inside of the wires themselves are free from corrosion or compromise.

I'll be testing DSC-SZL connectivity and also looking for the 60 ohm resistance at some point in the next day or two. Again, waiting for my body to heal after one of the first gym return visits in almost 6 months hah!

 

[SunglassesGuy]

not sure if 12.6VDC is healthy. you may want to research on that. when was the last time you charged the battery? btw - what ever happened to your brakes?

 

[platii]

12.6 is enough to power up the control unit.

 

[dan.trainor]

Guys. I figured it out.

It's a doozey and I don't even want to talk about it. Bit it has to do with relay 30G and wake-up. Turns out this relates to some similar problems I was seeing with other control modules that I thought I'd get to later, after figuring out DSC.

Learned a lot... hah! And using ISTA to help bleed the brakes is kind of neat!

 

[platii]

Thanks for the update.
So it is the supply power, is it intermittent as I still remember that it was checked ok?.
Good you found the cause.

 

[dan.trainor]

It was wake-up. I didn't have a full understanding of relay 30G and how it behaves. Basically, DSC never got woken up.... I did test pins but maybe I was testing with the wrong or bad conditions, I'm not sure. Either way, happy to have it back. Now to reassemble everything, work on a garage alignment good enough to get it to the pros. I MISS THIS CAR lol