light AUDI A4 1998 B5 / 1.G Brakes ESP Electrical Testing Workshop Manual

01-303

Note:
The operation manual for the VAS1978 wiring
harness repair kit generally forbids the repair of
any lines in the ABS or related systems. This rule
only pertains to the shielded lines in these
systems.

Ignition and electrical consumers switched
off before beginning testing (headlights,
lighting, fan, etc.).
For steps 13 through 16, raise the vehicle
until the wheels rotate freely. On vehicles
with manual transmission put the gear shift
lever in neutral. On vehicles with automatic
transmission move the selector lever to
position "N".
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01-309

Multi-pin connector at ABS control module
(w/EDL) -J104- Terminal
Connected to...

Terminal
25
Hydraulic unit; activation of left rear ABS outlet valve -
N136-
11
26
Hydraulic unit; activation of right front ABS inlet valve -N99-

5
27
Not assigned
-
28
Ground (GND) supply, terminal 31
-
29
Ground (GND) supply, terminal 31
-
30
Not assigned
-
31
Instrument cluster; activation of traction control indicator
light; (control module 4B0 907 389)
15
31
Rear left wheel speed sensor output; (control module 8D0
907 389/A/D/E)
-
32
Instrument cluster; ABS/EDL warning light activation
26
33
Not assigned
-
Electrical Wiring Diagrams, Troubleshooting & Component Locations
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01-311

Multi-pin connector at ABS control module
(w/EDL) -J104- Terminal
Connected to...

Terminal
40
Not assigned
-
41
Not assigned
-
42
Brake light switch -F; brake test switch
4
43
Not assigned
-
44
Traction control switch
6
45
Not assigned
-
46
Diagnostic connector; K-wire
7
47
Not assigned
-
48
Brake light switch -F-; brake light switch
2
49
ABS hydraulic unit -N55-; activation of pilot valve -1-
traction control -N225-
7
50
ABS hydraulic unit -N55-; activation of pilot valve -2-
traction control -N226-
6
51
Voltage supply; terminal 30 for hydraulic pump for
traction control -V156-;
-
Electrical Wiring Diagrams, Troubleshooting & Component Locations
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01-314

Multi-pin connector at ABS control
module (w/EDL) -J104- Terminal
Connected to...

Terminal
70
Left-rear wheel speed sensor output; (control module 4B0
907 389)
EWD
70
Instrument cluster; activation of traction control indicator
light (control module 8D0 907 389/A/D/E)
15
71
Speed sensor output rear right
EWD
72
not occupied; (control module 4B0 907 389)
-
72
Front left wheel speed sensor output; (control module 8D0
907 389/A/D/E)
EWD
73
not occupied; (control module 4B0 907 389)
-
73
Front right wheel speed sensor output; (control module 8D0
907 389/A/D/E)
EWD
74
Not assigned
-
75
Sensor for transverse acceleration -G200-; voltage supply;
(control module 4B0 907 389)
3
75
not occupied; (control module 8D0 907 389/A/D/E)
-
76
Parking brake warning light switch -F9-
EWD
Electrical Wiring Diagrams, Troubleshooting & Component Locations
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01-317
Notes:
For test table

The socket designations of the VAG1598 test box are identical to the terminal designations of the ABS control module
(w/EDL) -J104- in the wiring diagram. Incorrect test procedures can cause damage to the system. Do not bridge any
terminals other than those listed in the table.
Electrical Wiring Diagrams, Troubleshooting & Component Locations Specified values refer to readings on the VAG1526 and are not necessarily applicable for other test units.
If the measured values do not match specifications, carry out the corrective actions listed on the right side of the table.
Electrical Wiring Diagrams, Troubleshooting & Component Locations If values are obtained, also check wiring for intermittent loose terminals and short circuit to B+ and Ground (GND). This
applies especially to sporadic malfunctions.
Use the VAG1594 connector test kit for checking continuity (bridges).
If the measured values only differ slightly from the specifications, clean the sockets and harness connectors of the testers
and adapter leads (using contact spray G 000 700 04) and repeat the test. Before replacing actual components, check
wiring and connections once more. This is especially important if the specification for a resistance test is under 10 .
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01-331

Function test: ABS warning light -K47-
Test
step VAG
1598/20
sockets Test of
Test requirements
- Additional work stepsSpecified
value Corrective
action
17 - Function of ABS
warning light -K47- DTC memory checked and no DTC present
in DTC memory of ABS control module -
J104-. Ignition switched off Multi-pin connector connected to ABS
control module -J104- and retainer catch
engaged.

See continuation on next page
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01-332
Continuation: Function test: ABS warning light -K47-
Test
step VAG
1598/20
sockets Test of
Test
requirements
- Additional work
steps Specified value
Corrective action
17 - Function of
ABS warning
light -K47- - Switch on
ignition ABS warning light -
K47- lights up for two
(2) seconds and then
goes out. - If ABS warning light does not come on,
check voltage of electrical system and test
wiring from terminal 32 of ABS control
module -J104- to instrument cluster for short
circuit to Ground (GND).

See continuation on next page
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01-333
Continuation: Function test: ABS warning light -K47-
Test
step VAG
1598/20
sockets Test of
Test
requirements
- Additional work
steps Specified
value Corrective action
17 - Function of
ABS warning
light -K47-
Electrical Wiring Diagrams, Troubleshooting &
Component Locations
Repair Manual, Electrical Equipment, Repair Group
90; Instrument cluster
- The ABS warning lamp does not switch off after 2
seconds. The red "brake system malfunction" symbol
lights up after 2 seconds. Check wire from terminal 32
of ABS control module -J104- to instrument cluster for
short circuit to B+ or open circuit.
- If voltage of electrical system is OK and wiring from
terminal 32 of ABS control module -J104- to instrument
cluster is intact there is a malfunction in instrument
cluster.
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01-334

Function test: Red brake warning symbol
Test
step VAG
1598/20
sockets Test of
Test requirements
- Additional work stepsSpecified
value Corrective
action
18 - Function of red "brake
system malfunction"
symbol
Repair Manual, Brake System, Repair
Group 47

Brake fluid level is OK Function of ABS warning light -K47-
already checked in step 17. Multi-pin connector connected to ABS
control module -J104- and retainer
catch engaged. Switch on ignition

See continuation on next page
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01-335
Continuation: Function test: Red brake warning symbol
Test
step VAG
1598/20
sockets Test of
Test requirements
- Additional work stepsSpecified value
Corrective action
18 - Function of red
"brake system
malfunction"
symbol
- Connect VAG1551 scan tool
and select address word 03
- For vehicles with automatic
transmission and instrument
cluster with DIS, depress the
brake pedal and select a
driving gear. The ABS/EDL indicator lamp
and the red "brake system
malfunction" symbol light up.
If the traction control indicator
light is OK, it lights up as
well. Repair Manual,
Electrical Equipment, Repair Group 90; Instrument cluster
- Malfunction in
instrument cluster
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