Yet another ABS/ASC question

DaleE

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Mar 29, 2021
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Hi folks. Newly registered to the forum, but I've been lurking and reading (and reading, and reading) all the posts here related to the wearisome ABS/ASC fault on our cars. I have a '99 Z3 with the 2.3 (actually 2.5) engine.

My ABS and ASC lights went on in the fall. Since I was unable to communicate with the car via my OBDII reader, I opted to replace all the wheel-speed sensors, rather than paying BMW to assess the problem. New sensors made no difference.

Spent the winter reading this forum and several others. Got some excellent ideas. Thank you!

A few weeks ago, I purchased the Foxwell NT510 scanner. Some folks here had luck with it, and their Amazon ad promised that the tool could address ABS/ASC.

I've been back and forth with a support person (in China) for a week now. Finally, today, I was able to access the ABS/ASC/DSC module with the code reader.

Still no joy. I'm getting this message:

Unknown control unit variant
Please copy the following data or click the
snapshot button for the image and send it
to the seller

System A304. Addr56
A0 01 16 48 96 04 03 69 60 23 78
04 20


Does anyone out there have any information that might help me out of this hellish quandary? Thank you.
 

Dino D

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Does that car have DSC or ASC?
I ask because DSC has an additional sensor over the ASC and is more advanced (complicated) in that it operates the brakes (ASC just c throttle).

When I had brake lights on it was wheel speed sensors but needed an older Snap On diagnostics tool to clear it (mine is early 98 so OBD, just the big round pin in the engine bay)
 

DaleE

Regular Member
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Mar 29, 2021
Messages
10
Thank for your reply, Dino. My car has ASC. I think DSC began later in my model year or in 2000. As for reading codes, I've tried almost everything. Today's readout was the furthest I've ever gotten, but still it doesn't solve the problem. I'm probably going with INPA next.

My fear (or hypothesis) is that mice have chewed the ABS loom, which would possibly explain why my reader can't communicate.
 

NZ00Z3

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Hi Dale.

Welcome to the forum from New Zealand.

I have a Foxwell NT530 scanner with BMW software. It's a good scanner. The NT510 is an earlier model than mine, but still a good scanner. If it has the BMW software, it should have no problems communicating with your ABS module in a 1999 Z3.

I take it that you have the BMW software on your scanner? If you don't then you are not going to be talking with the ABS module. It needs the BMW software.

The possibilities I can think of are:
- Not using a scanner with BMW software
- ABS module is so dead it will not communicate
- Wiring damage to the ABS module.

Do you have a set of wiring diagrams for your Z3? There a 6 sets of diagrams that cove the production run of the Z3. You need your car's build date, mm/yy. Go to the "Resources" section of this forum. See the blue ribbon at the top of your screen. On page 2 are the wiring diagrams. Each set has the build date that it covers in the bottom right corner of the first page.
 

DaleE

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Mar 29, 2021
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Thank you for your excellent reply, NZ00Z3!

I have the updated BMW software on my Foxwell scanner. In fact, I had to purchase an old Windows PC over the weekend to do it, since this is a Mac household, and Foxwell tech doesn't support Apple machines. But after all that nonsense, finally, late Sunday night, I managed to download the most recent BMW software onto my scan tool.

Your comment about the possibility of either a dead ABS module or wiring damage both hit home for me. See, I was planning to send the module in for a rebuild (to the tune of about two hundred USD), but wanted to first do everything possible to communicate with the car via a diagnostic tool And as for the wiring damage, as you've read, that's a distinct possibility. The barn where the Z3 sleeps is swarming with mice, and I suspect some of them have built a nest somewhere underneath.

I also appreciate your advice about the wiring diagrams. I own a Bentley manual, and I believe all the diagrams are there, but it's nice to know I can also access them here.

Thanks so much for your help!
 

andyglym

Shiny Dust Caps Make Your Zed Go Faster.
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Thank you for your excellent reply, NZ00Z3!

I have the updated BMW software on my Foxwell scanner. In fact, I had to purchase an old Windows PC over the weekend to do it, since this is a Mac household, and Foxwell tech doesn't support Apple machines. But after all that nonsense, finally, late Sunday night, I managed to download the most recent BMW software onto my scan tool.

Your comment about the possibility of either a dead ABS module or wiring damage both hit home for me. See, I was planning to send the module in for a rebuild (to the tune of about two hundred USD), but wanted to first do everything possible to communicate with the car via a diagnostic tool And as for the wiring damage, as you've read, that's a distinct possibility. The barn where the Z3 sleeps is swarming with mice, and I suspect some of them have built a nest somewhere underneath.

I also appreciate your advice about the wiring diagrams. I own a Bentley manual, and I believe all the diagrams are there, but it's nice to know I can also access them here.

Thanks so much for your help!
With regards to the mice issue, my car also lives in a barn on a farm. To combat the mice I have a small electric dehumidifier I place in my Zed when not in use, mice don't like noise and to date (6 years) I've not had a problem.
 

NZ00Z3

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With regards to the mice issue, my car also lives in a barn on a farm. To combat the mice I have a small electric dehumidifier I place in my Zed when not in use, mice don't like noise and to date (6 years) I've not had a problem.
It must sound the the Purring of a cat. :D
 

DaleE

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Mar 29, 2021
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And speaking of which, I tried to install a barn cat last summer. That did not end well.
 

DaleE

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Mar 29, 2021
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One last question: is there any fairly simple test I can perform to determine if the fault is with the ABS module, or with the wiring loom? My Foxwell reader will communicate with every other system on the vehicle except the ABS/ASC system. My feeling is that my next step is to get underneath and start examining wires. Only problem with that is: electrical fault troubleshooting fills me with anxiety and a sense of doom!
 

NZ00Z3

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The communications wire to the ABS unit is coloured White with a violet strip. If you see some chew marks, check for that coloured wire.

A long shot for communicating with the ABS module:
- With your Foxwell Scanner and BMW software, select the E36 model of car
- When the scanner asks you if the car is older than 03/98 say "yes"
- Select the ABS module from the list and see if it communicates.

What the above is doing is, it's talking to the ABS with an older communications protocol. It might work, it might not. It will not break anything.
 

DaleE

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NZ00Z3, I owe you a debt of profound gratitude. Your post caused me to go into the back yard and scan once again (4th or 5th time)--this time being more careful with my selections. Apparently, I'd been using the wrong build date. When I put in the correct date of 9/98, the Foxwell scanner DID, INDEED, COMMUNICATE!!

I've got a code 94: DTC--ASC: CAN data fault from DME/DDE and a code 71: DTC--ASC: Pump motor.

Finally, some actual progress toward a fix!

Next time I'm in New Zealand, the beers are definitely on me. Thank you.
 
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DaleE

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One more question, then: Codes 94 and 71 suggest that I need to send in the ABS unit for a rebuild, right?
 

NZ00Z3

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Yes the build date is important. The communication protocols for some modules changed at 03/98.

Glad to hear that you have the codes.

Code 94 is for a data share between the ABS module and the DME. Not sure what the story is with it.

Code 71 is for the normal pump connector solder joints problem. It very common.

If you are DIY handy and can use a solder iron, you can fix the code 71 problem. File attached. The repair may also fix the code 94 problem, but there are no guarantees it will.

Sending it in for a rebuild/repair may be the best bet.
 

Attachments

DaleE

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Mar 29, 2021
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Thank you so much, gentlemen. Now the issue becomes: do I attempt the fix myself, or do I send it to Module Masters for $150. In any event, the possibility of getting rid of those nagging codes, which have been bothering me since last fall, is a deep satisfaction to me.
 

NZ00Z3

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Send it to module Masters and be sure that it is fixed first time.
 

DaleE

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Mar 29, 2021
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Rebuild did the trick. Six months and over six hundred dollars, as I struggled, every which way, to find the cure. Today, for the first time since late summer of last year, my dash is free of CELs. Thanks folks.

Tried to delete this post, but can't see how to do that--only edit. As soon as I got on the road, the CELs returned. Of course they did. Back to the drawing board.
 
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DaleE

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Mar 29, 2021
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As soon as I accelerate, it once again pulls a code 71. I went in and cleared that code and tried again, but no joy. I'll call Module Masters on Monday and see what they say. Man am I ever sick of playing with this.
 
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