ABS Residual Bus Simulation for Audi S4 Conversion (AZB)

Hello everyone,

My friend owns an Audi A4 8D sedan that has been modified with an S4 engine (engine code AZB). I believe the car was manufactured in 1996 or 1997 and still has the ABS 5.0 system with the control unit located under the rear seats, and it doesn't have CAN bus. The problem now is that the S4 was only delivered with ABS 5.3, and as a result, an error is always stored in the engine control unit, depending on the coding.
If the control unit is programmed for all-wheel drive without ASR/ESP (10611), error code 18014 - P1606 (Rough road information/engine torque from the ABS control unit - electrical fault in the circuit) will be stored. When encoding on ASR/ESP (10711), it throws an error due to a lack of communication with the ABS.

Does anyone know more about the communication between the ABS (Anti-lock Braking System) and the engine control unit (ECU)? Does anyone even know the IDs? How complex is a residual bus simulation of the ABS?

What is the model year of the engine?
I am simulating the ABS/ESP control unit, airbag system, and steering angle sensor for a BLG model year 2006.
If you're comfortable with AVR assembly language, I might send you the source code sometime.

Best regards,
Ingo

If I'm not mistaken, the engine should be from the 2000/2001 model year. So, it's definitely much older than yours.
Can you tell me what all you have to simulate for the ABS? Does the MSG constantly receive messages from the ABS, or does the MSG even request messages? I think that the process at the BLG (Bundesliga) has generally become more complicated.

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The engine should be from the model year 2000/2001, if I remember correctly. So, definitely older than yours.

That would be a V4.xx CAN matrix, while my BLG uses a V5.xx version, but it's mostly backward compatible.

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Can you tell me what all you have to simulate for the ABS?

;---------------------------------------------------------
Simulating an ABS/ESP control unit:
Brake 1.
Brake 2.
Brake 3.
Brake 4.

;---------------------------------------------------------
Airbag control unit simulator:
Airbag 1.

;---------------------------------------------------------
Simulated steering angle sensor:
Steering angle sensor 1.

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Does the MSG continuously receive messages from the ABS

?

Yes, they are all transmitted cyclically as broadcasts.

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or does the MSG even request messages?

No. "To my knowledge, it's not common to find this information on the powertrain CAN bus outside of diagnostics (at least not until around 2006 - I don't have any more recent information)."

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I think that, generally speaking, things have become more complicated at the BLG

.

Leaving things out is always easy...

Best regards,
Ingo

That already helps me a bit. How are the ABS messages structured exactly? Then I could test that using a CAN interface...

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That already helps me a bit. How are the ABS messages structured exactly? Then I could test that using a CAN interface...

As I said, if you have some experience with AVR assembly, send me your email address so you can get my firmware.


Best regards,
Ingo

Thank you for the offer!
Wouldn't it be easier if you just sent me a brief outline of the news? Since you wrote the AVR assembly code yourself, I assume you're familiar with it, right?