AUDI A3 1999 8L / 1.G ATW Engine Electronic Power Control Checking Service Manual

24-146
If indications do not resemble description:

Check switch

- Remove driver-side storage compartment.

Repair Manual, Body Interior, Repair Group
68; Instrument panel; Driver
-side storage
compartment, removing


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

If specified values are not obtained: - 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
- Depress accelerator pedal.

Specification: (no continuity)
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(EPC
) (E-Gas
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- Replace brake light switch / brake pedal switch.
Pa
ge 42 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
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24-147
If specified values are obtained:

- Check voltage supply

Checking voltage supply

If LED does not light up:
Electrical Wiring Diagrams, Troubleshooting & Component Locations - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
1 Chassis Ground (GND)

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

LED must light up.
- Check wire connection from terminal 1 or 3 of connector for open
circuit and short circuit to Ground (GND):
Pa
ge 43 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
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play?action=Goto&t
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24-148

- Repair open circuit or short circuit if
necessary.
If LED lights up:

- Checking activation.

Checking activation

- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

- Check 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
- Repair open circuit or short circuit if necessary.
Pa
ge 44 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.24.4

24-149


Clutch vacuum vent valve switch -F36-,
checking

Special tools and equipment

VAG1526A
VAG1527B
VAG1594A
VAG1598/31
VAS5051 with VAG5051/1
- or
VAG1551 with VAG1551/3A
Pa
ge 45 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
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11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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pair&id=AUDI.B5.FU06.24.4

24-150

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 control module for engine electronics
using "address word" 01 Page 01
-10
. Ignition
must remain switched on.
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 measuring value block
Q
Enter 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
1
2
3
4

Indicated on display
- Check Clutch Pedal Position (CPP) switch in display field 2.
Pa
ge 46 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
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11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
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pair&id=AUDI.B5.FU06.24.4

24-151


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
X0XX
(at clutch pedal not operated)

X1XX
(at clutch pedal operated)
Note
Value:X = no significance
Pa
ge 47 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.24.4

24-152
If indications do not resemble description:

Check switch

- Remove driver-side storage compartment.

Repair Manual, Body Interior, Repair Group
68; Instrument panel; Driver
-side storage
compartment, removing


- Disconnect harness connector at Clutch Pedal
Position (CPP) switch.

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


Specification: approx. 0

- Depress clutch pedal.


Specification: (no continuity)
If specified value is not obtained:

- Replace Clutch Pedal Position (CPP) switch.
If specified value is obtained:
Pa
ge 48 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.24.4

- Check voltage supply
Pa
ge 49 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.24.4

24-153

Checking voltage supply

If LED does not light up:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
If LED lights up: - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
1 Chassis Ground (GND)
- Switch ignition on.

LED must light up.
- Check wire connection from terminal 1 of connector to fuse for open
circuit:
- Repair open circuit if necessary.
- Checking activation.
Pa
ge 50 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.24.4