1998 AUDI A4 ATQ Engine Additional Signals Testing Workshop Manual

24-179

Read Measurin
g Value Block
Q
Input display group number XXX

When indicated on display:
- Press buttons -0-, -6- and -6- to select "display group number 066" and
press -Q- button to confirm input.
Read Measuring Value Block 66
1
2
3
4

Indicated on display:
- Check brake light/brake pedal switch in display field 2.

Display fields

1 2 3 4
Display group 066: Signals to Engine Control Module (ECM)
Display xxx km/h
XXXX xxx km/h XXXX
Indicated ACTUAL speed
Switch positions SPECIFIED speed Switch positions
Functional range
XX00
XX11
Specified value
XX00
(with brake pedal
not operated)

XX11
(with brake pedal
operated)
Notes
Value:
X = no significance.
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Switch points slightly offset
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24-180
If indications do not resemble description:

Check switch

- Remove driver-side storage compartment.

Repair Manual, Body
-Interior, Repair Group
68; Instrument Panel; Removing Driver
-Side
Storage Compartment


- Disconnect harness connector at brake light
switch and brake pedal switch.

Note:
Connector sockets are marked on the back side
of the connector.

- Connect multimeter between terminal 1 and 2 for resistance
measurement.

Specification: (no continuity)
- Depress accelerator pedal.

Specification: approx. 0
- Connect multimeter between terminal 3 and 4 for resistance
measurement.

Specification: approx. 0
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- Depress accelerator pedal.

Specification: (no continuity)
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24-181
If specified values are not obtained:

- Check adjustment of switch or

- Replace brake light switch / brake pedal
switch.
If specified values are obtained:

Checking voltage supply

- Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
1 Chassis Ground (GND)

LED must light up.
- Switch ignition on.
Harness connector
Terminal
Measure to
3 Chassis Ground (GND)

LED must light up.
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24-182
If LED does not light up:

- Check wire connection from terminal 1 or 3 of
connector for open circuit and short circuit to
Ground (GND):

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
- Repair open circuit or short circuit if
necessary.
If LED lights up:

Checking activation

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

- Check the following wire connections for open
circuit and short circuit to Ground (GND) and B+:

Harness connector
Terminal
VAG1598/31 test box
Socket
2 56
4 55
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- Repair open circuit or short circuit if
necessary.
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24-183

Clutch vacuum vent valve switch -F36-,
checking


Note:
This signal helps prevent excessive RPM
oscillations and tip-in shocks when clutch is
disengaged and is required for the cruise control
system.

Test sequence

- Connect VAS5051 tester or VAG1551 scan tool
and select the control module for engine
electronics using "address word" 01 Page 01
-
9 .

Ignition must remain switched on for this.Rapid data transfer
HELP
Select function XX

When indicated on display:
- Press buttons -0- and -8- to select "Read Measuring Value Block" and
press -Q- button to confirm input.
Read Measurin
g Value Block
Q
Input displa
y group number XXX

When indicated on display:
- Press buttons -0-, -6- and -6- to select "display group number 066" and
press -Q- button to confirm input.
Read Measuring Value Block 66

Indicated on display:
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