AUDI A8 2000 D2 / 1.G AHA Engine Throttle Valve Control Module Checking Owner's Manual

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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Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select "Read Measuring Value Block"
function 08, and press -Q- button to confirm input.
Read Measurin
g Value Block
HELP
Input display group number XXX

Indicated on display
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24-144

- Press buttons -0-, -0- and -3- to input display
group number 3 (003), and press -Q- button to
confirm input. Read Measuring Value Block 3 1 2 3 4

Indicated on display (1-4 = display fields)
- Compare display with specified values for throttle angle, (display field
3):

Display fields

1 2 3 4
Display group 3: Load measurement
Display xxx RPM xx.x g/s
xxx
xx.x BTDC
Indicates Engine speed
(in 40 RPM
steps) Mass air
flow Throttle angle Ignition timing
Range 0 - 6800 RPM ---
0 - 90
0.0 - 50.0
BTDC
Specified
value 0 RPM ---
0 - 5
0.0

--- --- If not as specified page 24
-146
, Evaluation of
display group 3
---
-
Open throttle valve slowly while monitoring degree ( ) value in display field 3. Value must increase uniformly over the entire range.
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-
Press button.
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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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24-147

Checking wiring

- Connect VAG1598/22 test box to ECM harness
connector page 01
-67
.

- Connect multimeter US1119 (Fluke 83 or
equivalent), using adapter cables from VW1594
connector test kit.

- Measure resistance to check for short circuit
between test box sockets 2 (Ground) and 75
(signal wire).


Test box sockets 2 and 75

Specified value:

- Switch multimeter to voltage (20 VDC)
measuring range.

- Switch ignition on.

- Check wiring for short circuit to B+.

Note voltage reading if applicable (if not 0
volts).
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- Switch ignition off.

- Continue test, depending on whether or not
voltage was measured page 24
-148
or page
Page 24
-149
.
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24-148

Continuation (with measured voltage)

If measured voltage was approx. 5 volts:
If measured voltage was approx. battery positive voltage (B+): - Disconnect 8-pin harness connector from throttle valve control module
-J338-.
- Connect multimeter US1119 (Fluke 83 or equivalent), using adapter
cables from VW1594 connector test kit.
- Measure resistance to check for short circuit between test box sockets
62 (power supply) and 75 (signal wire).

Test box sockets 62 and 75
Specified value:
- Check wiring at 8-pin connector, terminal 5 for short circuit to battery
B+.
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Continuation (with no measured voltage)

- Disconnect 8-pin harness connector from throttle
valve control module -J338-.

If wiring is OK: - Check wiring for open circuit between ECM/test box and 8-pin harness
connector.

Connector terminal 5 to ECM/test box socket 75
Specified value: max. 1.5
- 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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