1998 AUDI TT ignition

24-131

Check voltage supply throttle valve control
module

- Pull connector -2- off throttle valve control
module.

- Switch ignition on.

If specified values are not obtained: - Connect multimeter for voltage measurement as follows:Harness connector
Terminal
Specified value
2 + Ground (GND) about 5 V
2 + 6 about 5 V
- Check wire connections from Engine Control Module (ECM) to throttle
valve control module Page 24
-132
.
Pa
ge 24 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

24-134
Both the Throttle Position (TP) sensor -G79- and
the Sender -2- for accelerator pedal position -
G185- are located at the accelerator pedal and
communicate the driver's intentions to the ECM
completely independently of each other. Both
sensors are stored in one housing.

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 measurin
g value block
Q
Enter display group number XXX

When indicated on display
- Press buttons -0-, -6- and -2- to select "display group number 062" and
press -Q- button to confirm input.
Read Measuring Value Block 62
1
2
3
4

Indicated on display
- Check specified values for E-gas potentiometer voltages in display
fields 3 and 4.
Pa
ge 27 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

24-137

Checking voltage supply of Throttle Position
(TP) sensor

- Remove driver-side storage compartment.

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


- Disconnect harness connector for accelerator
pedal position sensor.

- Switch ignition on.

If specified values are obtained: - Connect multimeter for voltage measurement as follows:Harness connector
Terminal
Specified value
1 + Ground (GND) about 5 V
1 + 5 about 5 V
2 + Ground (GND) about 5 V
2 + 3 about 5 V
Pa
ge 30 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

24-139

Kick down function, adapting

If the sensor for accelerator pedal position or the
Engine Control Module (ECM) is replaced on a
vehicle with automatic transmission, the kick
down function must be adapted.

Special tools and equipment

or
Requirements
Procedure
VAS5051 with VAG5051/1VAG1551 with VAG1551/3ANo DTCs in DTC memory, check DTC memory Page 01
-16
.
Engine not running, ignition switched on.
- 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.
Pa
ge 33 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

24-144

Note:
For safety reasons, the instruction from the
accelerator pedal sensor (potentiometer) to the
ECM to open the throttle valve is suppressed
when brake is being operated. This requires the
brake light switch signal and also the brake pedal
switch signal in the control module. If brake pedal
is operated with accelerator pedal constantly
depressed, engine is immediately regulated
down to idle speed. A faulty switch can lead to
undesired regulation.

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 measurin
g 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.
Pa
ge 39 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

24-147
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
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

24-150

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
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