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Steffarn Profi-Schrauber


Joined: 09/17/2003 Posts: 632 Karma: +3 / -0
2003 Audi A4 Avant Premium Support
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19-02-2004, 21:03 Subject: Retrofitting ESD/ASR for Audi A4 |
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Hi, can I retrofit an electronic stability control (ESC) or anti-slip regulation (ASR) system to my Audi?
If the costs can be kept low, that would be great.
However, I'm very concerned if a completely new ABS unit is needed.
[Audi A4 B5 TDI AFN, manufactured in 1997]
Does anyone know anything about that?  B.Eng (FH) u. KFZ Meister
Seit 06/10: Audi A4 1,9 TDI Avant Quattro mit AVF.

Translated on 28-09-2026, 18:17.
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mersente Guest
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19-02-2004, 21:54 Subject: Retrofitting ESD/ASR for Audi A4 |
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Hello, and that's exactly what you'll need, along with the steering angle sensor and the lateral acceleration sensor.
I wouldn't add any extra features, as it's all too expensive, unless you can find a car that's been in an accident and has those parts available at a low price.
Translated on 28-09-2026, 18:18.
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Steffarn Profi-Schrauber


Joined: 09/17/2003 Posts: 632 Karma: +3 / -0
2003 Audi A4 Avant Premium Support
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19-02-2004, 21:58 Subject: Retrofitting ESD/ASR for Audi A4 |
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Are you sure that I also need a steering wheel sensor for an Electronic Stability Program (ESP)?
I thought it detected wheel slip by, for example, when the inner wheel spins during a turn.
Am I correct in assuming that the spinning wheel is braked during an Electronic Stability Program (ESP) event, or is there something in the differential within the transmission involved?  B.Eng (FH) u. KFZ Meister
Seit 06/10: Audi A4 1,9 TDI Avant Quattro mit AVF.

Translated on 28-09-2026, 18:19.
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mersente Guest
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19-02-2004, 22:22 Subject: Retrofitting ESD/ASR for Audi A4 |
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There are no components installed in the differential. The EDS control unit calculates data based on the steering angle and lateral acceleration to determine when to intervene.
Translated on 28-09-2026, 18:19.
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Bertil Profi-Schrauber

Joined: 04/15/2002 Posts: 5628 Karma: +108 / -0
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19-02-2004, 22:42 Subject: Retrofitting ESD/ASR for Audi A4 |
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mersente wrote: | | ...The EDS control unit calculates data for intervention based on the steering angle and lateral acceleration. |
The EDS (Electronic Stability System) does not require steering angle or lateral acceleration sensors, while the ESP (Electronic Stability Program) requires both.
For the EDS (Electronic Differential Lock), the wheel sensors are sufficient (which the ABS already includes), because here, only large speed differences from right to left (and vice versa) are compensated for by targeted braking. Smaller speed differences, such as those typically encountered during cornering, are not taken into account. Gruß Bertil
Skoda 5E5 CZDA + Mini R50 W10 + VW ID.3 + Fiat Ducato 250 + 161 DX
*** Technische Anfragen per PN werden von mir nicht beantwortet! ***
Translated on 28-09-2026, 18:20.
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19-02-2004, 23:24 Subject: Retrofitting ESD/ASR for Audi A4 |
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Yes, that's right, I probably mixed those up.
Translated on 28-09-2026, 18:21.
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Steffarn Profi-Schrauber


Joined: 09/17/2003 Posts: 632 Karma: +3 / -0
2003 Audi A4 Avant Premium Support
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20-02-2004, 8:55 Subject: Retrofitting ESD/ASR for Audi A4 |
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@ Bertil
Are wheel sensors sufficient for the Electronic Stability System (EDS)?
Did you mean ESD (Electrostatic Discharge) or (electronic slip differential)?
"That's actually what I'm concerned about, because when I accelerate out of a corner, the inside wheel always spins and I can't get going! In that respect, the ESD is essentially the same as the ASR."
I don't need ESP anyway.
What I'm interested in is what the difference is between a vehicle with standard ABS and a vehicle with ESD and ASR.
Steering angle sensor?
Engine control unit?
ABS control unit?
4. Other speed sensors?
5. Alternative ABS control unit?
6. Is it perhaps only possible through coding? B.Eng (FH) u. KFZ Meister
Seit 06/10: Audi A4 1,9 TDI Avant Quattro mit AVF.

Translated on 28-09-2026, 18:22.
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Bertil Profi-Schrauber

Joined: 04/15/2002 Posts: 5628 Karma: +108 / -0
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20-02-2004, 9:28 Subject: Retrofitting ESD/ASR for Audi A4 |
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Hi,
Steffarn wrote: | | Are wheel sensors sufficient for the EDS? |
Yes.
Quote: | | Did you mean ESD or (electronic slip differential)? |
Yes, of course. I just misspelled the letters...
Quote: |
"That's actually what I'm most concerned about, because when I accelerate out of a turn, the inside wheel always spins and I can't get going! In that regard, the ESD is essentially the same as the ASR."
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It's a bit of both. ASR primarily reduces engine power, while ESD actively intervenes with braking.
Quote: |
I don't need ESP anyway.
What I'm interested in is what the difference is between a vehicle with standard ABS and a vehicle with ESD and ASR.
1. Steering angle sensor |
No is not required for either ASR or ESD.
Quote: | | 2. Engine control unit? |
It could be different. The ABS/EDS control unit and the engine control unit must be connected via a fast data bus in order to implement power-limiting commands. This is not necessary without ASR/ESD.
Quote: | | 3.ABS control unit? |
See above for the engine control unit (ECU). Additionally, your ABS control unit is missing the software for the ASR/ESD function.
Quote: | | 4. Other speed sensors? |
No, not usually.
Quote: | | 5.Alternative ABS control unit? |
Point 3 is applicable.
Quote: | | 6. Can this perhaps only be done through coding? |
For newer engine control units (ECUs) that are already connected via CAN bus (or a similar system), this might be possible (like Ulf's new Polo), but I doubt it would work with older systems that operate completely independently. Gruß Bertil
Skoda 5E5 CZDA + Mini R50 W10 + VW ID.3 + Fiat Ducato 250 + 161 DX
*** Technische Anfragen per PN werden von mir nicht beantwortet! ***
Translated on 28-09-2026, 18:25.
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Jan6K

Joined: 04/12/2002 Posts: 4741 Karma: +107 / -0 Location: Hagen
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20-02-2004, 10:54 Subject: Retrofitting ESD/ASR for Audi A4 |
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HI,
Are you sure that the ABS hardware is sufficient for the ESD function? I immediately believe that it is for the input (wheel sensors), but I have my doubts about the output. While the ABS can reduce braking power (if the driver brakes), can the same hardware also brake a wheel without the driver's intervention (i.e., essentially increase braking power)?
Best regards,
Jan. 1Z5 CFHF  / AHB H4D 
Translated on 28-09-2026, 18:28.
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Bertil Profi-Schrauber

Joined: 04/15/2002 Posts: 5628 Karma: +108 / -0
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20-02-2004, 11:16 Subject: Retrofitting ESD/ASR for Audi A4 |
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Jan6K wrote: | HI,
Are you sure that the ABS hardware is sufficient for the ESD function? I immediately believe that it is for the input (wheel sensors), but I have my doubts about the output. While the ABS can reduce braking power (if the driver brakes), can the same hardware also brake a wheel without the driver's intervention (i.e., essentially increase braking power)?
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So, at least the newer systems with brake assist can do that. Gruß Bertil
Skoda 5E5 CZDA + Mini R50 W10 + VW ID.3 + Fiat Ducato 250 + 161 DX
*** Technische Anfragen per PN werden von mir nicht beantwortet! ***
Translated on 28-09-2026, 18:29.
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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20-02-2004, 11:34 Subject: Retrofitting ESD/ASR for Audi A4 |
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I believe the baby's name is EDS, according to my knowledge.
Electronic differential lock.
(but that doesn't change anything about the technical discussion  ).
m;
Translated on 28-09-2026, 18:30.
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Bertil Profi-Schrauber

Joined: 04/15/2002 Posts: 5628 Karma: +108 / -0
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20-02-2004, 13:15 Subject: Retrofitting ESD/ASR for Audi A4 |
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Hi Martin,
dieselmartin wrote: | The baby's name is already in my knowledge base, EDS.
Electronic differential lock.
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Absolutely correct. According to the user manual and also the brochure, this good device is called EDS. So, I didn't misspell it. Gruß Bertil
Skoda 5E5 CZDA + Mini R50 W10 + VW ID.3 + Fiat Ducato 250 + 161 DX
*** Technische Anfragen per PN werden von mir nicht beantwortet! ***
Translated on 28-09-2026, 18:31.
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Gremlin Guest
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20-02-2004, 20:01 Subject: Retrofitting ESD/ASR for Audi A4 |
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HI,
Are you sure that the ABS hardware is sufficient for the ESD function? I immediately believe that it is for the input (wheel sensors), but I have my doubts about the output. While the ABS can reduce braking power (if the driver brakes), can the same hardware also brake a wheel without the driver's intervention (i.e., essentially increase braking power)?
So, at least the newer systems with brake assist can do that.
Hehe... it's not that simple after all...
The braking assistant in models like the Golf and others is a purely mechanical system in the rear axle.
A basic, standalone ABS system cannot perform the functions of EDS or ESP.
'This requires more control valves. Specifically, the hydraulic system needs to be able to isolate the wheel brake cylinders from the pedal and apply pressure to them separately. So, instead of two valves per wheel, you would need three. This would bring the total number of valves to 12.'
The Teves Mk60 is actually available in both versions.
However, I can't imagine that they would still install such a basic ABS system.
Although, VW would probably handle it smoothly...
My Octavia was ordered without ESP, and it's also supposed to lack EDS. However, it seems that the EDS is still functioning, which is similar to the situation with the missing VTG.
But with a 1997 A4? In that case, you'll probably have to examine it very carefully... but I don't see much hope.
CU Gremlin.
Translated on 28-09-2026, 18:33.
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Steffarn Profi-Schrauber


Joined: 09/17/2003 Posts: 632 Karma: +3 / -0
2003 Audi A4 Avant Premium Support
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20-02-2004, 20:45 Subject: Retrofitting ESD/ASR for Audi A4 |
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Well, it seems like there are few options to improve things without essentially subsidizing the industry with money.
Perhaps someday I'll find an A4 that's been in an accident where I can remove the ABS unit.
For my next car, I will definitely make sure it has Quattro, then I can gladly do without the ESD.  B.Eng (FH) u. KFZ Meister
Seit 06/10: Audi A4 1,9 TDI Avant Quattro mit AVF.

Translated on 28-09-2026, 18:35.
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Bertil Profi-Schrauber

Joined: 04/15/2002 Posts: 5628 Karma: +108 / -0
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20-02-2004, 21:15 Subject: Retrofitting ESD/ASR for Audi A4 |
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Gremlin wrote: | Bertil wrote: |
So, at least the newer systems with brake assist can do that. |
Hehe... it's not that simple after all...
The braking assistant in models like the Golf and others is a purely mechanical system in the rear axle.
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Okay Gremlin, I should have expressed myself more clearly:
So, at least the newer systems with electronic brake assist can do that.
I am aware that the G4 has a mechanical brake assist system.
How can I tell if I have a mechanical allergy or not? Gruß Bertil
Skoda 5E5 CZDA + Mini R50 W10 + VW ID.3 + Fiat Ducato 250 + 161 DX
*** Technische Anfragen per PN werden von mir nicht beantwortet! ***
Translated on 28-09-2026, 18:36.
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Gremlin Guest
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20-02-2004, 22:30 Subject: Retrofitting ESD/ASR for Audi A4 |
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I am aware that the G4 has a mechanical brake assist system.
How can I actually tell if I have a mechanical BA or not?
Good question. G4 and similar models have a mechanical system. With Audi's Bosch ABS, it should be an electronic system.
Here's what I found:
At VOLKSWAGEN, hydraulic systems are used for...
Brake assist system currently available in the Polo model year.
2002, in the Passat 2001, and in a D-class vehicle.
to be used.
The mechanical brake assist is installed in...
'These are used in current models of the Golf (4) and Bora.'
The mechanical one can at least be checked while it's stationary.
The brake pedal must be pressed while the engine is running and...
to be kicked by a stationary vehicle, so that...
Full vacuum support is ensured.
The mechanical brake assist system is activated when...
pressed brake pedal above the activation point.
schwelle aktiviert. When triggering the...
A clicking sound can be heard in the mechanical brake assist system.
Bremskraftverstärker zu hören. Dbrake pedal
can now be easily released and operated with minimal force.
will be.
When the brake pedal is fully released, ...
Release the brake assist (no hydraulic system).
Pressure in the braking system.
CU Gremlin.
Translated on 28-09-2026, 18:40.
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