sensor AUDI A8 1998 D2 / 1.G AHA Engine Throttle Valve Control Module Checking Workshop Manual

24-129

Function

Idle speed stabilization is integrated in the
throttle valve control module -J338-. In the
housing opposite the throttle valve are Throttle
Position (TP) sensor -G69-, Closed Throttle
Position (CTP) switch -F60-, throttle drive -G186-
and angle sensor -1- for throttle drive -G187-.

The housing should not be opened.
The individual components cannot be replaced or
mechanically adjusted. All adjustments are
accomplished by the VAG1551 Scan Tool (ST)
using the "Basic Setting" function 04.
If the complete throttle valve control module is
without power (i.e. disconnected), the throttle
valve assumes a mechanical closed throttle
position that results in an increased idle speed of
1200-1300 RPM (with engine at operating
temperature).
If only the Throttle Position (TP) actuator -V60- is
without power, the throttle valve also assumes a
mechanical closed throttle position (limp-home
position), but because the signal from the CTP
switch -F60- can still be recognized, a nearly
"normal" idle speed of approx. 900 RPM is
maintained with a corresponding reduction of the
ignition timing advance.
If the Engine Control Module (ECM) recognizes a
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malfunction in the angle sensor -1- for throttle
drive -G187-, it switches the power off for throttle
drive -G186-,and the throttle valve again
assumes the mechanical closed throttle position
(limp-home position).
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24-136

Throttle drive and angle sensor for
throttle drive, checking


Note:
Throttle drive -G186- and angle sensor -1- for
throttle drive -G187- are located in the throttle
valve control module -J338-.

Test conditions

Throttle valve in closed throttle position; if
necessary adjust accelerator pedal cable

Repair Manual, Fuel Supply System, Repair
Group 20


Cruise control adjustment OK
Power supply for throttle valve control
module OK; checking page 24
-130


Engine coolant temperature at least 80 C
(176 F)

Automatic transmission selector lever in "P"
or "N"
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24-143

Throttle Position (TP) sensor, checking


Note:
The Throttle Position (TP) sensor -G69- is
located inside the throttle valve control module -
J338-.

Test conditions

Throttle valve in closed throttle position; if
necessary adjust accelerator pedal cable

Repair Manual, Fuel Supply System, Repair
Group 20


Cruise control adjustment OK
Power supply for throttle valve control
module OK; checking page 24
-130


Checking

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with ignition
switched; engine not running) page 01
-8 .
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24-145

- Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
input.

- Switch ignition off.

Note:
The values displayed in display field 3 depend on
the calibration of the Throttle Position (TP)
sensor and do not correspond with the actual
throttle valve opening in degrees. The maximum
displayed value is 90.0 . If the throttle angle value does not increase
uniformly:

- Replace throttle valve control module -J338-.

- Carry out adaptation of throttle valve control
module to ECM page 24
-150
.

- Check readiness code page 01
-70
. If
Diagnostic Trouble Code (DTC) memory has
been erased, or ECM was disconnected,
generate new readiness code page 01
-73
.
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24-146
Evaluation of display group 3 Display
group: 3


Display field:
3
Possible malfunction cause
Corrective action
0.0
Open circuit or short circuit to B+ in signal wire between throttle position
sensor -G69- and engine control module
Malfunction in Ground for -G69-- Check wiring page
24
-147

99.0
Short circuit to Ground in signal wire between throttle position sensor -G69-
and engine control module
Malfunction in voltage supply for -G69-
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24-150

Throttle valve control module,
adaptation to Engine Control Module
(ECM)

If the throttle valve control module -J338- is
removed and installed, or replaced, adaptation of
the throttle valve control module to the Motronic
ECM is required.
During "adaptation" with ignition switched on and
the engine not running, the Motronic ECM
"learns" the closed throttle position (CTP), wide
open throttle (WOT) and other positions of the
throttle valve control module, and a characteristic
curve of the relationship between Throttle
Position (TP) sensor -G69- and angle sensor for
throttle drive -G187-.

Required special tools and test equipment

VAG1551 or VAG1552 Scan Tool (ST) with
VAG1551/3 adapter cable

Test conditions
No malfunctions stored in DTC memory
page 01
-16


Throttle valve in closed throttle position; if
necessary adjust accelerator pedal cable
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24-151

Test procedure

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with ignition
switched on; engine not running) page 01
-8 .
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -4- to select "Basic Setting" function 04, and
press -Q- button to confirm input.
System in Basic Settin
g
HELP
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -6- and -0- to input display group number 60 (060),
and press -Q- button to confirm input.
System in Basic Setting 60 1 2 3 4

Indicated on display (1-4 display fields)
Notes:
After confirming input of display group 60, adaptation is started. The
Throttle Position (TP)sensor is positioned in the closed throttle, wide
open throttle and limp-home positions. Following this procedure, other
intermediate steps will create a characteristic curve of the relationship
between Throttle Position (TP) sensor -G69- and angle sensor for
throttle drive -G187-. The Motronic ECM stores these values in permanent memory.
Afterward, the throttle valve assumes the starting position.
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