AUDI A8 1998 D2 / 1.G AHA Engine On Board Diagnostic Manual Online

control head repeatedly until the display is
erased)
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01-60

Test sequence

- Connect VAG1551/VAG1552 Scan Tool (ST)
and press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (engine running at
idle) page 01
-8 .
Rapid data transfer
HELP
Select function XX

Indicated on display
Note:
By pressing the HELP button an overview of possible functions will be
printed out. - Operate scan tool while observing messages on display:
- Press buttons -0- and -4 to select "Basic Setting" function 04, and
press -Q- button to confirm input.
System in Basic Setting
Q
Input display group number XXX

Indicated on display
Note:
Display group number 0 (000) is used as an example to demonstrate the
procedure.
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01-61
To change to another display group:

Display
group
VAG1551
VAG1552
higher Press -3-
button Press
button
lower Press -1-
button Press
button skip Press -C-
button Press -C-
button

- Press -0- button three times to input display
group number 0 (000), and press -Q- button to
confirm input. System in Basic Setting 1 2 3 4 5 6 7 8 9 10

Indicated on display
Notes:
In display group 0 the measuring values are displayed in decimal
form. The display can be printed out by pressing the PRINT button.
-
If specified values were attained in all display fields, press button to
advance through program sequence.
Rapid data transfer
HELP
Select function XX

Indicated on display
-
Press buttons -0- and -6- to select "End Output" function 06, and press
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-Q- button to confirm input.
- If one of the specified values is not attained page 01
-63
evaluation
of display group 000.
- Continue by using procedures in "Corrective action" column.
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01-62

Display group 000 (display in decimal values)

Engine running at idle; ECM in "Basic Setting" function 04
Display fields
Specified
value Corresponds to
1
2
3 4
5 6
7 8
9 10
Idle learn value (additive) for O2S control, bank 2 115-141 -0.65 to +0.65
ms





Idle learn value (additive) for O2S control, bank 1
115-141


-0.65 to +0.65
ms



O2S control bank 2 (if outside of tolerance, conduct test
drive) 77-179 -10 to +10 %




O2S control bank 1 (if outside of tolerance, conduct test
drive)
77-179
-10 to +10 %


Learn value-idle air flow 118-138 -5.0 to +5.0 kg/h



Idle air control value
118-138
-5.0 to +5.0 kg/h

Throttle angle 0-12
0-5


Engine speed (with electrical consumers switched off)
All-wheel drive vehicles
Front-wheel drive vehicles

62-74
74-86

620-740 RPM
740-860 RPM

Engine load (with electrical consumers switched off) 20-50 1.0-2.5 ms
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Engine coolant temperature (necessary for "Basic Setting")
170-204
80-105 C
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01-63
Display group 000-evaluation Display field
1
Possible malfunction cause
Corrective action
greater than
204
Engine coolant temperature (ECT) sensor -
G62- - Check ECT sensor page 24
-75
less than 170

Engine coolant temperature (ECT) sensor -
G62- - Check ECT sensor page 24
-75


Coolant thermostat faulty (open)
Repair Manual, 2.8 Liter V6 5V Engine Mechanical,
Repair Group 19 - Check thermostat
Display field
2
Possible malfunction cause
Corrective action
greater than
50
Electrical consumers switched on- Switch off electrical consumers

Oxygen Sensor (O2S) control at limit- Check HO2S and O2S control before TWC page 24
-
22

- Check HO2S aging, bank 1, sensor 1 (before TWC)
page 24
-60

- Check HO2S aging, bank 2, sensor 1 (before TWC)
page 24
-63

less than 20

Intake air leaks ("false air")- Check intake air system for leaks page 24
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Fuel pressure regulator faulty or hose
disconnected - Check fuel pressure regulator page 24
-111
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01-64

Display field 3
Possible malfunction cause
Corrective action
less than 62
(all-wheel drive)
or
less than 74
(front-wheel drive)
Drive range selected
Throttle valve control module faulty- Move selector lever to "P" or "N" position
- Check idle speed page 24
-16
- Check throttle valve control module page 24
-128

less than 74
(front-wheel drive)
Supply voltage (terminal 15) to terminal 10
of Engine Control Module (ECM) missing - Check supply voltage (terminal 15) to terminal
10 of ECM using applicable wiring diagram
greater than 74
(all-wheel drive)
or
greater less than 86
(front-wheel drive) Closed Throttle Position (CTP) switch open
Throttle valve control module faulty
Intake air leaks ("false air")- Check idle speed page 24
-16
- Check throttle valve control module page 24
-128

- Check intake air system for leaks page 24
-
126

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01-65

Display field 4
Possible malfunction cause
Corrective action
less than 0 (Not possible) ---
greater than 12

Adaptation of throttle valve control module to
ECM not complete - Check adaptation of throttle valve control
module page 24
-150

greater than 12

Throttle Position (TP) sensor in throttle valve
control module faulty - Check throttle valve control module page 24
-
128

greater than 12

Throttle valve mechanism sticking
Contamination in intake air ducting near throttle
valve - Check by visual inspection and repair as
necessary
greater than 12
Accelerator pedal cable adjustment
Repair Manual, Fuel Supply System, Repair
Group 20
- Adjust accelerator pedal cable
Display fields 5
+ 6
Possible malfunction cause
Corrective action
less than 118

Intake air leaks ("false air") after throttle valve- Check intake air system for leaks page 24
-
126

greater than
138
Increased engine load- Switch off electrical consumers

Throttle valve mechanism sticking
Contamination in intake air ducting near throttle
valve - Check by visual inspection and repair as
necessary
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