B7 RS4 race car - Airbag controller module and ABS

[frogracing]

Hi

I am working on a B7 RS4 race car that will see mostly hillclimb and light stage rally duties (details of the build here: https://www.frogracing.us/garage/froooog).
The car has a full FIA rollcage for stage rally and most of the interior wiring that was not needed was removed. This includes the entire airbag system wiring and the airbag controller module.
The steering wheel angle sensor had the connectors trimmed down to fit the racing steering wheel hub with the quick disconnect but the angle sensor is still in place (just no steering wheel connected to it).

I am trying to get the ABS system out of limp mode as it seems unhappy to not be able to communicate with the airbag controller module (which is not there and will not come back as the wiring is gone). Right now the brake light blinks, traction control is deactivated, etc....

The engine management has been working fine, no performance issue with the car in the current configuration (see scan below). However the braking is problematic as the brake bias seems absolutely ridiculous in limp mode (we went off during testing but were lucky:

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).

I have a few questions:
1. Is there a way to code the ABS to make it work without an airbag controller module?
2. Is the steering wheel angle sensor necessary for the ABS to work?
3. Does the ABS module manage the differentials and traction control?
4. Does the intermittent issue with the steering wheel angle sensor (Supply Voltage Terminal 30) normal when the steering wheel is not connected?
5. As a bonus question, can I disable the TPMS as the wheels will never have TPMS in them? (I saw on the forum, let me know if this is correct: Instrument Cluster, select channel 061, then subtract 512 from it)

Thanks for your help and patience, I am completely new to this platform!
Frog Racing

Sunday,19,January,2025,14:01:21:39996
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 24.7.1.0 (x64)  HEX-NET2 CB: 0.4643.5
Data version: 20240919 DS356.3
www.Ross-Tech.com


VIN: WUARU78E87N904344   License Plate: FROOOOG
Mileage: 215450km-133874mi   Repair Order:



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 8E (8E - Audi A4/S4/RS4 B6/B7 (2001 > 2008))
Scan: 01 02 03 08 09 0F 11 15 16 17 18 25 36 37 45 46 55 56 57 65
          67 69 75 76 77
 
VIN: WUARU78E87N904344   Mileage: 215450km-133874miles
-------------------------------------------------------------------------------
Address 01: Engine        Labels:. 079-910-560-BNS1.lbl
   Part No SW: 8E1 910 560 A    HW: 8E1 907 560
   Component: 4.2L V8/4V FSI     ª0060 
   Revision: 57H13---    Serial number: XXXXXXXXXXXXXX
   Coding: 01040009180F0160
   Shop #: WSC 01307 444 58753
   VCID: 241A9F30B2D23CEA1B3-8070
   VINID: 9E54629472152077890040C410C91FCBE5

2 Faults Found:
049489 - No Communications with Airbag Control Module
               U0151 - 008 -
             Freeze Frame:
                    Fault Status: 01101000
                    Fault Priority: 0
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 215436 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 797 /min
                    Load: 22.7 %
                    Speed: 0.0 km/h
                    Temperature: 72.0°C
                    Temperature: 24.0°C
                    Absolute Pres.: 960.0 mbar
                    Voltage: 13.970 V

006435 - Please Check DTC Memory of ECU Number 2
               P1923 - 008 -
             Freeze Frame:
                    Fault Status: 01101000
                    Fault Priority: 0
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 215436 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 0 /min
                    Load: 0.0 %
                    Speed: 0.0 km/h
                    Temperature: 81.0°C
                    Temperature: 30.0°C
                    Absolute Pres.: 960.0 mbar
                    Voltage: 12.319 V

Readiness: 0000 1101

-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 8E0-910-517.clb
   Part No SW: 8E0 910 517 G    HW: 8E0 614 517 BD
   Component: ESP8 quattro    H06 0150 
   Revision: 00000000    Serial number: 00000000000000
   Coding: 0004533
   Shop #: WSC 06335 000 00000
   VCID: 2B08740CDF0CF392DA9-807E

2 Faults Found:
01321 - Control Module for Airbags (J234)
            004 - No Signal/Communication
             Freeze Frame:
                    Fault Status: 01100100
                    Fault Priority: 1
                    Fault Frequency: 1
                    Reset counter: 40
                    Time Indication: 0

             Freeze Frame:
                    Hex Value: 0x0000
                    Hex Value: 0x4020
                    Hex Value: 0x0013
                    Hex Value: 0x1690
                    Hex Value: 0x0001

01826 - Sensor for Steering Angle (G85); Supply Voltage Terminal 30
            000 - - - Intermittent
             Freeze Frame:
                    Fault Status: 00100000
                    Fault Priority: 3
                    Fault Frequency: 16
                    Reset counter: 39
                    Time Indication: 0

             Freeze Frame:
                    Hex Value: 0x0000
                    Hex Value: 0x4220
                    Hex Value: 0x0024
                    Hex Value: 0x0184
                    Hex Value: 0x0001


-------------------------------------------------------------------------------
Address 08: Auto HVAC        Labels: 8E0-820-043.lbl
   Part No: 8E0 820 043 BM
   Component:   A4 Klimaautomat   2833 
   Coding: 00000
   Shop #: WSC 00000 
   VCID: 6D8CBA1424883DA284D-5160

2 Faults Found:
01172 - Temperature Sensor; Driver's Heated Seat (G59)
            30-00 - Open or Short to Plus
01171 - Temperature Sensor; Passenger Side Heated Seat (G60)
            30-00 - Open or Short to Plus

-------------------------------------------------------------------------------
Address 09: Cent. Elect.        Labels: 8E0-907-279-8EC.lbl
   Part No: 8E0 907 279 N
   Component: int. Lastmodul  USA 0907 
   Coding: 01023
   Shop #: WSC 65536 
   VCID: 3D2C4A5434686D2274D-4B00

No fault code found.

-------------------------------------------------------------------------------
Address 11: Engine II        Labels:. 079-910-560-BNS2.lbl
   Part No SW: 8E1 910 560 A    HW: 8E1 907 560
   Component: 4.2L V8/4V FSI     ª0060 
   Revision: 57H13---    Serial number: XXXXXXXXXXXXXX
   Coding: 01040009180F0160
   Shop #: WSC 01307 444 58753
   VCID: 241A9F30B2D23CEA1B3-8070

2 Faults Found:
049489 - No Communications with Airbag Control Module
               U0151 - 008 -
             Freeze Frame:
                    Fault Status: 01101000
                    Fault Priority: 0
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 215436 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 797 /min
                    Load: 22.7 %
                    Speed: 0.0 km/h
                    Temperature: 72.0°C
                    Temperature: 24.0°C
                    Absolute Pres.: 960.0 mbar
                    Voltage: 13.843 V

005491 - Left Engine Mount Solenoid Valve (N144)
               P1573 - 004 - Open Circuit
             Freeze Frame:
                    Fault Status: 01100100
                    Fault Priority: 0
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 215436 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 181 /min
                    Load: 77.6 %
                    Speed: 0.0 km/h
                    Temperature: 81.0°C
                    Temperature: 30.0°C
                    Absolute Pres.: 960.0 mbar
                    Voltage: 10.287 V


-------------------------------------------------------------------------------
Address 16: Steering wheel        Labels: 8E0-953-549-T.lbl
   Part No: 8E0 953 549 T
   Component: Lenksáulenmodul     0301 
   Coding: 04441
   Shop #: WSC 06335 
   VCID: 44DA3FB057821CEA3B3-4B00

4 Faults Found:
01426 - Controls in Steering Wheel (E221)
            49-00 - No Communications
01304 - Radio
            49-00 - No Communications
01303 - Telephone Transceiver (R36)
            49-00 - No Communications
01301 - Control Module for Voice Recognition (J507)
            49-00 - No Communications

-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 8E0-920-9xx-8EC.clb
   Part No SW: 8E0 920 982 R    HW: 8E0 920 982 R
   Component: KOMBI+WFS 4     H14 0100 
   Revision: 0100        Serial number: 00000000000000
   Coding: 0023268
   Shop #: WSC 02440 067 57207
   VCID: 3D2C4A5431686D2274D-5184

4 Faults Found:
01321 - Control Module for Airbags (J234)
            004 - No Signal/Communication
01304 - Radio
            004 - No Signal/Communication
01303 - Telephone Transceiver (R36)
            004 - No Signal/Communication
01300 - Control Module for Navigation with CD-Rom (J401)
            004 - No Signal/Communication

-------------------------------------------------------------------------------
Address 25: Immobilizer        Labels: 8E0-920-9xx-8EC.clb
   Part No SW: 8E0 920 982 R    HW: 8E0 920 982 R
   Component: KOMBI+WFS 4     H14 0100 
   Revision: 0100        Serial number: 00000000000000
   Coding: 0023268
   Shop #: WSC 02440 067 57207
   VCID: 3D2C4A5431686D2274D-5184

4 Faults Found:
01321 - Control Module for Airbags (J234)
            004 - No Signal/Communication
01304 - Radio
            004 - No Signal/Communication
01303 - Telephone Transceiver (R36)
            004 - No Signal/Communication
01300 - Control Module for Navigation with CD-Rom (J401)
            004 - No Signal/Communication

-------------------------------------------------------------------------------
Address 46: Central Conv.        Labels:. 8E0-959-433-MAX.clb
   Part No: 8E0 959 433 CG
   Component: Komfortgerát T7B    4135 
   Coding: 11820
   Shop #: WSC 06335 
   VCID: 78A29B405BCA880A67B-4B00

   Subsystem 1 - Part No: 8E1959801G
   Component: Tõrsteuer.FS BRM 0706 

   Subsystem 2 - Part No: 8E1959802G
   Component: Tõrsteuer.BF BRM 0706 

   Subsystem 3 - Part No: 8E0959801E
   Component: Tõrsteuer.HL BRM 0606 

   Component: Tõrsteuer.HR BRM 0606 

4 Faults Found:
01134 - Alarm Horn (H12)
            49-00 - No Communications
00962 - Alarm via. Tilt Sensor
            35-00 - -
01366 - Opened Due to Crash Signal
            36-00 - Open Circuit
00955 - Key 1
            35-10 - - - Intermittent

-------------------------------------------------------------------------------
Address 55: Headlight Range        Labels: 4F0-910-357.lbl
   Part No SW: 4F0 910 357 F    HW: 4F0 907 357 F
   Component: AFS 1           H01 0020 
   Revision: 00000001    Serial number:               
   Coding: 0000019
   Shop #: WSC 06335 000 00000
   VCID: 29048E04D5F0E182285-807C

   Subsystem 1 - Part No: 8E0 941 329 A
   Component: AFS-Modul links H03 0020

   Subsystem 2 - Part No: 8E0 941 329 A
   Component: AFS-Modul rechtsH03 0020

No fault code found.

-------------------------------------------------------------------------------
Address 65: Tire Pressure        Labels: 8E0-907-273.lbl
   Part No SW: 8E0 907 273 A    HW: 8E0 907 273 A
   Component: Reifendruck 3   H04 0130 
   Coding: 0062523
   Shop #: WSC 02197 785 00200
   VCID: 2A067108D0D6EA9A21F-5160

2 Faults Found:
01521 - Sensor for Tire Pressure
            004 - No Signal/Communication - MIL ON
             Freeze Frame:
                    Fault Status: 11100100
                    Fault Priority: 3
                    Fault Frequency: 1
                    Reset counter: 40
                    Time Indication: 0

             Freeze Frame:
                    (no units): 49.0
                    Voltage: 14.00 V
                    (no units): 61.0
                        Not Recogn.
                        Not Recogn.
                        Not Recogn.
                        Not Recogn.
                    Inj. On Time: 0.00 ms

02214 - Tire Pressure Warning
            000 - -
             Freeze Frame:
                    Fault Status: 01100000
                    Fault Priority: 1
                    Fault Frequency: 89
                    Reset counter: 40
                    Time Indication: 0

             Freeze Frame:
                    (no units): 58.0
                    Temperature: 20.0°C
                    Error Code: 1
                        Not Recogn.
                        Not Recogn.
                        Not Recogn.
                        Not Recogn.
                    Lateral Accel.: -123.07 m/s*2


-------------------------------------------------------------------------------
Address 76: Park Assist        Labels: 8E0-919-283-8EC.lbl
   Part No SW: 8E0 919 283 D    HW: 8E0 919 283 D
   Component: Parkhilfe 4-Kan H06 0010 
   Revision: 00H06000    Serial number: 00067802030629
   Coding: 0000304
   Shop #: WSC 01117 444 84384
   VCID: 31346664FD009942E05-5184

1 Fault Found:
01543 - Parking Aid Warning Chime (H15)
            009 - Open or Short to Ground
             Freeze Frame:
                    Fault Status: 01101001
                    Fault Priority: 3
                    Fault Frequency: 1
                    Reset counter: 5
                    Time Indication: 0


End----------(Elapsed Time: 05:36, VBatt start/end: 13.6V/13.7V)-----------

 

[Uwe]

1. Is there a way to code the ABS to make it work without an airbag controller module?

I doubt it. Airbags were not an "option" in these cars. However, I'm skeptical that's what's making the ABS be funky with respect to brake bias.

2. Is the steering wheel angle sensor necessary for the ABS to work?

I believe so. I expect it uses that info to determine what differences in wheels speeds are acceptable, and also that isn't just ABS, it's also ESP.

3. Does the ABS module manage the differentials and traction control?

I believe the differentials that that car are purely mechanical. However, the ABS does manage traction control, both in terms of applying the brake on a wheel that it thinks is spinning too fast to force torque to the other side, and by requesting a reduction of torque from the engine.

4. Does the intermittent issue with the steering wheel angle sensor (Supply Voltage Terminal 30) normal when the steering wheel is not connected?

Unclear. Is the ABS getting proper readings from the steering angle sensor?

5. As a bonus question, can I disable the TPMS as the wheels will never have TPMS in them? (I saw on the forum, let me know if this is correct: Instrument Cluster, select channel 061, then subtract 512 from it)

Sounds plausible.

For the airbags, you can also try subtracting 16 from the value in channel 060, but since airbags were not optional, I'm not confident this will do much.

-Uwe-

PS: The parking job is supposed to be done like this:

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[frogracing]

I believe the differentials that that car are purely mechanical. However, the ABS does manage traction control, both in terms of applying the brake on a wheel that it thinks is spinning too fast to force torque to the other side, and by requesting a reduction of torque from the engine.

Only the center differential is a Torsen limited slip, the front and rear are open diffs (they make an aftermarket LSD for it). The car uses an electronic differential lock (EDL) which I believe is part of the Bosch ABS unit to mimic a limited slip diff by braking the wheel that is slipping and transferring the torque through the open diff. The car also has an electronic brake-force distribution (EBD) that is basically an electronic brake proportioning valve that adjusts dynamically the front-rear distribution based on the pitch angle and speed. In our Subaru STis the EBD brakes each rear wheel individually (like if you had 2 dynamic rear proportioning valves), it is unclear to me how the RS4 EBD exactly works.
After our parking job in the woods, we realized that the steering wheel angle sensor was not calibrated (it looks like we have to go through the calibration procedure every time we hit the kill switch). The car turned left right on the application of the brakes, not sure if it's the EBD or the EDL that applied the brakes on one side based on the bogus signal from the steering angle sensor. I expected everything to be disabled but I am not sure what is actually still active in the current configuration.
The weight distribution of the car has changed significantly with the rear being 200lbs lighter with the cage which can also probably affect the default brake bias setup.

Unclear. Is the ABS getting proper readings from the steering angle sensor?

Is there a way I can visualize the signal from the steering angle sensor?
There are only the airbag control module and the intermittent steering angle sensor power that are reported as fault in the ABS so not sure what else it could be that would cause the ABS to disable everything.

Sounds plausible.

For the airbags, you can also try subtracting 16 from the value in channel 060, but since airbags were not optional, I'm not confident this will do much.

I'll try that and report back.

PS: The parking job is supposed to be done like this:

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Agreed! I need to practice more

 

[Uwe]

Is there a way I can visualize the signal from the steering angle sensor?

Sure, MVB 005 in the ABS has:

Steering Angle Sensor (G85)
Rotation Rate Sensor (G202)
Brake Pressure Sensor (G201)
Lateral Acceler. Sensor (G200)

With front wheels pointed straight ahead and steering wheel centered, steering angle should indicate within a degree or two of zero. Turning the steering wheel in one direction should get you positive readings, while turning it in the opposite direction should get you negative readings. This is easiest to test with the engine running.

-Uwe-

 

[frogracing]

Some progress:
- I was able to disable the TPMS by substracting 512 from channel 61
- Subtracting 16 from the value in channel 060

For the Airbags, I found in the engine long coding a bit for the Airbag installation but when I tried to write the new code I got a 'Request out of range' error (see screenshot below).
Does this mean that this value is not allowed or just that we can't write this field at all?

https://lh4.googleusercontent.com/n...b2IzNox8ZrVG4mZfU763LWJWonobkyqW5EeTbow=w1280

I tried to get into the ABS coding but it says to contact Ross-Tech so I will need some help with that if there is something I can do here.

https://lh5.googleusercontent.com/e...OeXXkQLrsDBJLfNFnlQoHHuVztZYQ-LBjDjYsHQ=w1280

Finally I did some logging of the steering angle sensor data. There is some data coming in but most of it is gibberish, I rarely get an integer value in any of the fields like if the encoding was wrong (See video below).

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Note that the video was with the engine not running but I get similar results with the engine running (I am able to graph a value once in a while when it reads a number).
Could it be a problem with the steering angle sensor or did I do something wrong trying to read the data?

Thanks for the help!

 

[Uwe]

Note that the video was with the engine not running but I get similar results with the engine running

Well that sure is special!

For laughs, look at some of the other MVBs, for example 001, which should have wheel speeds.

I'm kinda thinking your ABS controller is just out to lunch.

-Uwe-

 

[Dr Sheldon]

2. Is the steering wheel angle sensor necessary for the ABS to work?

Pure ABS has no use for a SAS. However ESP which is often integrated with ABS does for sure.

 

[frogracing]

Pure ABS has no use for a SAS. However ESP which is often integrated with ABS does for sure.

The ABS shouldn't have any use for the Airbags and yet it complains that the airbag controller module is not present. Since EDL and EDB are also using the ABS system, I'm guessing that the ABS subsystem probably requires a proper signal from the SAS to be happy. I'm just not sure if everything gets disabled when the SAS or Airbag are missing or just parts of the ABS subsystem.

 

[Dr Sheldon]

The ABS shouldn't have any use for the Airbags and yet it complains that the airbag controller module is not present.

You would be surprised at "what needs what" in the modern car !!

Airbag and ABS - both safety systems and you think they dont need /want to talk ? Silly really !!

Secondary Collision Avoidance is just one example where they interact.

I'm guessing

That is correct !

 

[MasterTommy]

Regardless of the airbag question, I really don’t see the brakes working properly (or at least the ABS being happy) without the steering angle sensor, which is as fundamental as wheel speed and inertial sensors. And there isn’t really a clear division anymore between ABS and ESP regarding which sensor inputs are used and which aren’t. All systems need all 3 types of sensors. The control strategy of the ABS function (e.g. how much wheel lock is allowed during braking action) also has a predictive component based on the inertia of the vehicle and steering angle.

I understand that the primary function of the ABS module isn’t relevant for your use-case, but the ABS module will probably refuse to do any secondary functions (which are important for your use-case). if it doesn’t think it can do its normal job. If this cannot be solved through coding/adaptations, and the unit does not use additional parameters/dataset that can be modified, modifying the software will be the only option. Might just be easier to get a steering angle sensor set up properly. Now, there might be aftermarket steering angle sensors that are compatible with your setup?

On a sidenote, i have no experience with ESP8 systems, only newer. I do have ESP8 experience on motorcycles, and they rely on more than just wheel speed sensors.

 

[Dr Sheldon]

I really don’t see the brakes working properly (or at least the ABS being happy) without the steering angle sensor,

ABS does not need or have any use for a Steering Angle Sensor - None !!

All ABS will do is to release and reapply brake pressure when it detects wheel slip on one or mere wheels. It will do this regardless of Steering Wheel Angle.


With ESP, The SAS will tell the Module which direction (Steering Angle) the driver wishes to go - (Desired). It will also note the Speed of Steering Wheel Rotation.

The Yaw rate sensor will tell the Module which direction the car is in fact travelling (Actual)

So if there i a mismatch between Desired and Actual then ESP will intervene. It can make adjustments Engine / Power and has the ability to brake one or more wheels independently of each other - Think of it as it having 4 brake Pedals (one for each Wheel)

As ESP became more advanced inputs such as Acceleration, Lateral, Longitudinal, Brake Pressure etc were added to improve it.

(e.g. how much wheel lock is allowed during braking action)

Wheel Lock is not allowed. ABS will intervene before that. As soon as a Wheel Speed is Reduced by x% (maybe 20 or 30) ABS will be alert, ready willing and able to take action.

The Clue is in the name - ANTI LOCK - Not Lock and Control - Very different concepts !!

Also has a predictive component based on the inertia of the vehicle and steering

You are describing ESP here. That is not ABS - Never was or will be !

I do have ESP8 experience on motorcycles, and they rely on more than just wheel speed sensors.

ESP is much the same principle be it on a Moped, a car, a lorry or an Aeroplane - Desired and Actual.


I hope that helps as it should bust all the Myths on what these systems do and loosely how. I cant help with the misdemeanours OP is pursuing as all I do all day is Diagnose and Factory Spec cars !! I have a team to do the nut and bolt bits.

Never had the urge to modify a car. I really dont work on my own cars if can help it. Just bribe the boys at work.

I got work for a short time not a hard time

 

[Dr Sheldon]

What I do not know is how your ESP (that is exactly what is fitted to your car) will operate with all but the 4 WSS's and Brake Pedal Switch disconnected ?

Will it still operate as Pure and Simple ABS ?? Only one way to find out ?

 

[frogracing]

I was able to solve the issue with the steering angle sensor:

01826 - Sensor for Steering Angle (G85); Supply Voltage Terminal 30

It turns out this code will re-appear every time the car loses power (usually the kill switch in the race car) and the ECU won't read any steering angle sensor signal until the sensor is re-calibrated.

I followed the procedure documented here: http://wiki.ross-tech.com/wiki/index.php/Audi_A4_(8E)_Brake_Electronics_(Bosch_8.0)#Coding

Sensor for Steering Angle (G85)​

[Select]
[03 - ABS Brakes]

[Fault Codes - 02]
[Done, Go Back]

Start Engine (session still running).

Turn steering wheel at least 30 ° left and back straight ahead.

[Meas. Blocks - 08]
Group 005 Field 1 (Steering Angle Sensor -G85-)
Specification: 0.0 °
Tolerance (when straight): ±5.0 °
[Done, Go Back]

[Security Access - 16]
Enter 40168
[Do It!]

[Basic Settings - 04]
Group 001
[Go!]
[Done, Go Back]

[Fault Codes - 02]
All fault codes should have disappeared.
[Done, Go Back]

[Close Controller, Go Back - 06]

After doing this I finally get proper readings from the steering wheel angle sensor and the code is gone. I just have the Airbag control module code and the 1486 Function Test Activated code for which I'll have to drive the car to resolve.

 

[Dr Sheldon]

It turns out this code will re-appear every time the car loses power

Power it with a 9v Battery - Battery connected toa12v USB from t30 and bingo

 

[frogracing]

Power it with a 9v Battery - Battery connected toa12v USB from t30 and bingo

Do you have any idea where this terminal is located?

 

[frogracing]

I tried to follow the instructions at http://wiki.ross-tech.com/wiki/index.php/ESP_System_Function_Test and https://forums.ross-tech.com/index.php?threads/33642/
It doesn't look like I can get the test started no matter the pressure on the brake pedal, none of the lights change on the dash. If I go in
[03-ABS]
Start [Basic Setting] 003
It says 'Test status' and 'Enabled' but the ESP/ABS/EPC lights stay on and the BRAKE light is flashing. I checked the brake pressure reading is above 30 bar, no matter what combo I try, the lights never change and doing the driving procedure never completes the test.

Is there another way to perform the test to resolve the 1486 Function Test Activated?

Also any info on the J104/Bosch 8.0 Coding?

 

[DrPeter]

Hello,

We have seen before that the "System Function Test" fault code will not clear if the ABS controller has certain fault codes.

In your case, it appears the "No Signal/Communication" fault with the Airbag controller is most likely the cause of your concerns.

There’s no documented coding for the ABS controller to exclude the Airbag controllers, likely due to the 1998 mandate for Airbags in most USA vehicles, and the Bosch 8.0 ABS system, introduced in/around 2009. So, such coding probably does not exist.. Ref: ref: 49 CFR 571.208

As I see it now, you can try three things:

1. Check if the ABS controller supports the Basic Settings group (103) and use the Security Access code 40168.
   (This used to be a secret function, but in some ABS controllers, it can "turn off" the System Function Test, maybe?)
2. Temporarily reconnect the Airbag controller and its wiring. Then, clear the ABS fault codes and perform the System Function Test. Be sure the Airbag controller is securely mounted to the vehicle.
3. Consider installing non-ABS brakes specifically designed for rally or race vehicles.

Personally, I prefer being in direct control of the brakes in a rally or race setting.

Disclaimer: The suggestions provided in this Ross-Tech forum post are for informational purposes only and should be used at your own risk. We are not responsible for any issues, damages, or consequences resulting from their implementation. Be safe!


Hope this helps,

drpeter

 

[frogracing]

Unfortunately putting the airbag controller in is not an option anymore at this point, it is an insane amount of wires that have been cut as far back as possible in the dash. Everything was working without the airbag controller before the car was reset after the battery was disconnected for the cage building (this is why I thought removing the airbag controller wiring would be fine).
I will try the Basic Settings 103 otherwise I'll have to bypass the ABS completely and also loose the EDL functionality which will force me to change the diffs for mechanical LSDs.

 

[DrPeter]

Was it Carroll Shelby once said: (paraphrased) ?

"You can’t win without the right equipment, and the right equipment isn’t cheap."

drpeter

 

[frogracing]

So finally found the correct sequence to complete the test:
[03-ABS]
Start [Basic Setting]
Choose 'System Test Activation Function' or Group '003' and Go
It will show 'Test Enabled'
Then go to Group '103' and Go
It will switch to 'System Test OFF'
Done, Go Back
The code will be gone.

All the ABS lights are still like a Christmas tree on restart just from the remaining Airbag controller error. I have to take the car for a test drive to see if the ABS is fully disabled or not.