1998 AUDI A8 engine

24-140
Explanation of 4-digit display
Explanation when display field is = 0
x
x
x
x
Display group 55
0 A/C compressor off (0 = A/C compressor off; 1 = A/C compressor on)
0 Shift lever in P or N (0 = Shift lever in P or N; 1 = Shift lever in 2/3/4/R/D)
0 Idle air control boost (0 = no idle air control boost, for all-wheel drive vehicles; 1 = idle air control boost, for
front-wheel drive vehicles)
0 always "0"
Note:
The increased idle speed (raised rpm) on vehicles with front-wheel drive is attained if there is power supplied (B+, 15er) to
terminal 10 of the engine control module.
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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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24-144

- 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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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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