1995 AUDI A4 engine

24-145

Throttle Valve Control Module -J338,
checking

The throttle valve control module housing
contains the following components:

CAUTION!

The housing should NOT be opened.

Throttle drive -G186 (power accelerator
actuation) (This is an electric motor activated by
the engine control module. The motor opens
the throttle valve by applying force to overcome
the spring pressure.)
Angle sensor -1- for throttle drive (power
accelerator actuation) -G187
Angle sensor -2- for throttle drive (power
accelerator actuation) -G188

Notes:
The angle sensors are in the form of
potentiometers (variable resistors). Each sends
its own separate signal to inform the engine
control module of the position of the throttle
valve (i.e. one of the signals is redundant).
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24-146

Throttle valve control module,
adaptation

The adaptation process enables the Engine
Control Module (ECM) to learn the different
positions of the throttle valve with the ignition
switched on and the engine not running. These
positions are stored in the control module. The
feedback signal indicating the position of the
throttle valve comes from the two angle sensors
for throttle valve drive.
If the Throttle Valve Control Module -J338 or the
ECM is removed and installed or replaced, or if
the voltage (power) supply to the ECM is
interrupted, an adaptation must be carried out.
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24-147
The learning process (adaptation process) is
carried out:

By selecting "Basic Setting" (function 04),
Display Group 060 with the ignition switched
on.
Automatically if the ignition is switched on for at
least 6 seconds without operating the starter or
depressing the accelerator, and if the Engine
Control Module (ECM) registers a "learning
requirement." (In this case, however, there is no
way of knowing whether the adaptation process
was successful or not.) The engine control
module will register a learning requirement if
the previously stored voltage readings from the
angle sensors do not correspond (within a
certain tolerance range) to the new voltage
readings.

Note:
The engine will not start during automatic
adaptation.
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24-148

Test conditions for adaptation of throttle
valve control module

No malfunctions stored in DTC memory
Page 01
-15
, check DTC memory

Engine not running, ignition switched on
Accelerator pedal not depressed
Coolant temperature between 5 C and
100 C (Display group 004, display field 3)

Intake air temperature less than 100 C

Voltage supply to engine control module
greater than 11Volt, Checking Page 28
-32

- 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.
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24-150
When the -Q- button is pressed the throttle valve
positioner will be switched mechanically.
In this condition the throttle valve is pulled into an
"emergency running" or default position by a
mechanical spring in the throttle valve control
module. The values supplied by the two angle
sensors for this emergency running position are
stored in the Engine Control Module (ECM).
The throttle valve is then opened by a
predetermined amount. As soon as it reaches
this position the current supply to the throttle
valve positioner is again disconnected. The
spring should then close the throttle valve
mechanically to the previously learned default
position within a specified period of time (spring
test).
The throttle valve positioner then closes the
throttle valve and the values supplied by the
angle sensors in the throttle valve control module
are stored in the Engine Control Module (ECM).
If the ECM disconnects the current supply to the
throttle valve positioner while the vehicle is being
driven, the result will be an increase in idling
speed with fluctuating engine RPM (hunting) and
very slow throttle response.
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24-152

Note:
If the adaptation process is interrupted by the
control unit, the cause could be one of the
following:

The throttle valve is unable to close completely
(e.g. because of dirt).
The harness connectors (e.g.: at throttle valve
control module) are loose, not properly
connected or the contacts at the connector are
corroded or bent.
Battery voltage too low.
Throttle valve control module or wiring is
faulty.
The engine was started or the accelerator pedal
was depressed during the adaptation process.
Distortion of throttle valve housing (check bolts:
10 Nm)
When the adaptation process is interrupted the
message "Function is unknown or cannot be
carried out at the moment" will appear on the
fault reader display. The adaptation process will
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start again automatically the next time the
ignition is switched on (for several seconds).

-
End engine basic setting by pressing the
button.

- Press buttons -0- and -6- to select "End Output"
function and confirm input with -Q- button.
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24-153

Angle sensor -1- for throttle drive
(power accelerator actuation) -G187-
and angle sensor -2- for throttle drive
(power accelerator actuation) -G188,
checking

The angle sensor -1- for throttle drive (power
accelerator actuation) -G187 and angle sensor -
2- for throttle drive (power accelerator actuation)
-G188 inform the engine control module of the
position of the throttle valve. Both angle sensors
are located in the throttle valve control module.

- 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
Q
Input displa
y group number
XXX

Indicated on display
- Press buttons -0-, -6- and -2- to select "display group number 062" and
confirm entry with -Q- button.
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