1997 AUDI A4 engine

01-39

EDL

Electronic Differential Lock
The Electronic Differential Lock (EDL) is a
traction control aid for driving away from a
standstill. An electronically-controlled brake
application at the wheel that is spinning provides
a torque reaction point for the differential. This
enables the wheel with better traction to make
use of the engine power. EDL is effective in both
forward and reverse.
EDL is part of the basic configuration of vehicles
with All Wheel Drive (AWD). Although EDL only
regulates the front wheels on vehicles with Front
Wheel Drive (FWD), EDL regulates all four
wheels on vehicles with All Wheel Drive (AWD).
This makes it possible to eliminate the driver
operated mechanical differential lock.
Pa
ge 5 of 10 Descri
ption of s
ystems
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU02.01.4

01-42

ASR

Anti-Slip Regulation (ASR)
The ASR option is only available on Front Wheel
Drive (FWD) vehicles. Observe control module
coding for these vehicles. The function of ASR
requires an exchange of signals between the
ABS control module -J104-, the Engine Control
Module (ECM) and the Transmission Control
Module (TCM). The control modules
communicate with each other.

There are two communication systems at work:

- Data is transferred via several single wires.

- Data is transferred via the CAN-bus. The
CAN-bus only contains two lines. These
transfer all required data.

To determine which communication system is
transferring data, use the "Check control module
version" function and check the table "Control
module versions".
Pa
ge 8 of 10 Descri
ption of s
ystems
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU02.01.4

01-43
ASR prevents the wheels being powered from
spinning during acceleration by reducing engine
load. It is active throughout the entire speed
range. The EDL and ASR functions work in
combination during vehicle acceleration.
ASR can be switched on and off by pressing the
traction control button in the center of the center
console. ASR is re-activated on its own when the
ignition is switched on. When the traction control
button is operated, the ASR indicator lamp lights
up in the instrument cluster. During adjustment
mode, the indicator lamp blinks three times per
second.
Pa
ge 9 of 10 Descri
ption of s
ystems
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU02.01.4