AUDI A4 1997 B5 / 1.G APB Engine Additional Signals Checking User Guide

24-188


Specified value: (no continuity)

- Depress brake pedal.


Specified value: approx.: 0

- Connect hand-held multimeter for resistance
measurement between terminals 3 and 4.


Specified value: approx.: 0

- Depress brake pedal.


Specified value: (no continuity)
If specifications are not obtained:

- Check adjustment or replace brake light/brake
pedal switch.
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24-189
If specifications are not met:

Check voltage supply

- Connect VAG1527 B between following sockets
on harness connector:

Harness connector
terminal
Measure
against
1 Ground (GND)


The LED must come on
Harness connector
terminal
Measure
against
3 Ground (GND)

- Switch ignition on.


The LED must come on
If LED does not come on:

- Check wiring connection from terminal 1 or 3 of
connector for open circuit (fuse) or short circuit
to Ground (GND).
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Electrical Wiring Diagrams, Troubleshooting &
Component Locations
- If necessary eliminate open circuit or short
circuit to Ground (GND)
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24-190
If LED comes on:

Check activation

- Connect VAG1598/31 test box to wiring harness
for engine control module. Do not connect to the
engine control module itself Page 24
-20
.
Test the following wiring connections for open
circuits and short to B+ or Ground (GND):

Harness
connector
terminal
VAG1598/31 test box,
socket
2 56
4 55

- Repair any open/short circuit as necessary.
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24-191

Clutch Vacuum Vent Valve Switch -F36,
checking


Note:
This signal is used to avoid RPM over-oscillation
and load change impacts when changing gears
and is also used for the cruise control system.

Test sequence

- Connect vehicle diagnostic, testing and
information system VAS 5051 or VAG1551 scan
tool and select engine electronics control
module by entering address word "01" Page
01
-9 .
When doing this the ignition must be switched
on. Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select function "Read Measuring Value
Block" and confirm entry with -Q- button.
Read Measurin
g Value Block
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -6- and -6- to select "display group number 066" and
confirm entry with -Q- button.
Read Measuring Value Block 66

Indicated on display
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1
2
3
4
- Observe clutch vacuum vent switch switch in display field 2.
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24-192


Display fields

1 2 3 4
Display Group 066: Signals to engine control module
Display xxx km/h
X X X X xxx km/h 0 0 0 0
Indicates Actual speed
Switch positions Specified speed Switch positions
Work
range
X0XX
X1XX

Specified value
X0XX
Clutch pedal not depressed

X1XX
Clutch pedal depressed
Note
Value:
X = insignificant
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24-193
If display does not appear as described:

Check switch

- Remove storage compartment on driver's
side.

Repair Manual, Body Interior, Repair Group
68


- Disconnect harness connector on clutch
switch.

- Connect hand-held multimeter for resistance
measurement between terminals 1 and 2.

Note:
The connector slots are marked on the back side
of the connector.


Specified value: approx.: 0

- Depress clutch pedal.


Specified value: (no continuity)
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If specifications are not obtained:

- Replace clutch vacuum vent valve switch.
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24-194
If specification is obtained:

Check voltage supply

- Connect VAG1527 B between following sockets
on harness connector:

Harness connector
terminal
Measure
against
2 Ground (GND)

- Switch ignition on.


The LED must come on
If LED does not come on:

- Check wire connection from terminal 2 of
connector for open circuit (fuse) or short circuit
to Ground (GND).

Electrical Wiring Diagrams, Troubleshooting &
Component Locations

- If necessary eliminate open circuit or short
circuit to Ground (GND)
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