1998 AUDI A3 check engine

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Throttle valve control module, adapting

The adaptation teaches the Engine Control
Module (ECM) various positions of the throttle
valve when the ignition is on and the engine is
stopped. These positions are stored in the
control module The return communication
regarding the position of the throttle valve occurs
via the two angle sensors for throttle drive.
An adaptation must always be performed when
the throttle valve control module -J338- or the
Engine Control Module (ECM) are removed and
installed (or replaced) or if voltage supply to the
Engine Control Module (ECM) is interrupted.
The learning process (adaptation) occurs:

automatically if the ignition is switched on for at
least 10 seconds without operating starter and
accelerator pedal and the Engine Control
Module (ECM) recognizes "adaptation
required". (There will be no notification of
whether adaptation was successful or not
however). Adaptation required is recognized if
stored voltage values from the angle sensors
do not match actual measured voltage values
within a certain tolerance range.
via initiation of basic setting (function 04)
display group 060 with ignition on.
Pa
ge 13 of 51 Electronic En
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(EPC
) (E-Gas
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Note:
Engine will not start during automatic adaptation.

Special tools and equipment

or
Requirements
VAS5051 with VAG5051/1VAG1551 with VAG1551/3ANo DTCs in DTC memory, check DTC memory Page 01
-16
.
Engine not running, ignition switched on. Accelerator pedal not depressed. Coolant temperature 10 to 95 C. Intake air temperature 10 to 90 C. Supply voltage for Engine Control Module (ECM) more than 12.7
volts; checking Page 28
-36
.
Pa
ge 14 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
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11/21/2002 htt
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yp
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pair&id=AUDI.B5.FU06.24.4

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Procedure

- 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 -4- to select "Initiate basic setting" and press -Q-
button to confirm input.
Basic Settin
g
Q
Enter displa
y group number XXX

When indicated on display
After pressing Q-button, throttle valve actuator will be switched on without
current.
In this condition, the throttle valve will be drawn into an emergency
position by a mechanical spring, which is located in the throttle valve
control module. The values supplied by the two angle sensors in this
emergency position are stored by the Engine Control Module (ECM). - Press buttons -0-, -6- and -0- to select "display group number 060" and
press -Q- button to confirm input.
Pa
ge 15 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
), checkin
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11/21/2002 htt
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24-124
Next, the throttle valve is opened by a certain
value. If this value is reached, the throttle valve
actuator is once again de-energized. Now, the
mechanical spring must close the throttle valve to
the previously learned emergency position within
a specified time (spring test).
Then, the throttle valve is closed by the throttle
valve actuator; the values supplied by the angle
sensors in the throttle valve control unit are
stored by the Engine Control Module (ECM).
If Engine Control Module (ECM) should de-
energize throttle valve actuator during driving
operation, this is expressed by an increased,
surging idle speed (RPM). The engine accepts
gas only after great delay. System in basic setting 60
1
2
3
4

When indicated on display
- Check specified values for throttle valve control module in display fields
3 and 4.
Pa
ge 16 of 51 Electronic En
gine Power Control
(EPC
) (E-Gas
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11/21/2002 htt
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play?action=Goto&t
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pair&id=AUDI.B5.FU06.24.4

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Note:
The control module can abort adaptation for the
following reasons:

Throttle valve cannot be closed completely (e.g.
contamination).
Battery voltage is too low.
Throttle valve control module or wire connection
is faulty.
Engine is started during adaptation or
accelerator pedal is operated.
Tension of throttle valve housing (check
bolts).
After termination, tester displays "Function is
unknown or cannot be performed at the
moment". The next time the ignition is switched
on (several seconds), adaptation will be
automatically repeated.

- End basic adjustment of the engine by pressing
the key.
Rapid data transfer
HELP

Indicated on display (function selection):
Pa
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gine Power Control
(EPC
) (E-Gas
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24-128
Angle sensor 1 for throttle drive (power
accelerator actuation) -G187- and angle sensor 1
for throttle drive (power accelerator actuation) -
G188- inform the Engine Control Module (ECM)
about the position of the throttle valve. Both
angle sensors are located in the throttle valve
control module.

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 -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 1 and 2.
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(EPC
) (E-Gas
), checkin
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Display fields

1 2 3 4
Display group 062: E-Gas potentiometer voltages
Display
xx %
xx % xx % xx %
Indicated
Throttle valve angle
(angle sensor 1) Throttle valve angle
(angle sensor 2) Sensor 1 for
Pedal position Sensor 2 for
Pedal position
Specified value
3 to 93 %
97 to 3 % 12 to 97 % 4 to 49 %
Note:
Engine Control Module (ECM) calculates the
voltage values of the angle sensors in percent
relative to 5 volts and displays these percentage
values. (5 volts supply voltage represents 100
%).

- Observe display field 1 and 2.

- Slowly depress accelerator pedal completely.
Percent indication in display field 1 must rise
uniformly. In the process, the tolerance range of
3 to 93% is not completely utilized.
Percent indication in display field 2 must
decrease uniformly. The tolerance range 97 to 3
% is not used completely during this.
Pa
ge 22 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

24-131

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