1995 AUDI A8 AHA Engine On Board Diagnostic Workshop Manual

01-6
Functions under "Engine Electronics" address word 01: Function 01: Check Control Module
Version Ignition switched on -or- Engine running at idle
Function 02: Check DTC Memory Engine running at idle, otherwise crank engine with starter motor for at least 5 sec.,
then do not switch ignition off
Function 03: Output Diagnostic
Test Mode Ignition switched on
Function 04: Basic Setting Engine running at idle
Function 07: Code Control Module Ignition switched on
Function 08: Read Measuring
Value Block Ignition switched on -or- Engine running at idle -or- Driving
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01-7
Modes under address word 33: Mode 1: Transfer diagnostic data Ignition switched on -or- Engine running at idle
Mode 2: Transfer operating conditions Ignition switched on -or- Engine running at idle
Mode 3: Check DTC memory Ignition switched on -or- Engine running at idle
Mode 4: Erase diagnosis information Ignition switched on -or- Engine running at idle
Mode 5: Output of HO2S signals Ignition switched on -or- Engine running at idle
Mode 6: Transfer measuring values Ignition switched on -or- Engine running at idle
Mode 7: Check DTC memory Ignition switched on -or- Engine running at idle Under Address word 33, Modes 1-7 can be addressed.
Under Mode 1, individual measuring values can be displayed. Mode 1 is not recommended for use in an Audi Service
department, because these values can be displayed much more precisely using address word 01 and "Basic Setting"
function 04 or "Read Measuring Value Block" function 08.
Mode 2 shows the operating conditions under which the stored malfunctions were recognized.
With Mode 3, DTC memory is checked-with Mode 4, DTC memory is erased.
Mode 5 shows the statistical value of the oxygen sensors as mandated by law. As these values have no direct bearing on
oxygen sensor diagnosis, Mode 5 is of no particular value in an Audi Service department.
Under Mode 6, values can be checked for components and systems that are not continuously monitored.
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With Mode 7 all malfunctions can be checked, even if they have not switched on the Malfunction Indicator Lamp (MIL) (if
the MIL has not been switched on, there is no malfunction recognized under Mode 3)
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01-8

VAG1551/VAG1552 Scan Tool (ST),
connecting and selecting "Engine
Electronics" address word 01


WARNING!

When driving or riding in an airbag-equipped
vehicle, NEVER hold the scan tool or other
test equipment in your hands or lap while in
motion. Objects between you and the airbag
increase the risk of injury in an accident.
During a test drive in an airbag-equipped
vehicle, test equipment must always be
fastened to and operated from the rear seat
by a second technician.

Required special tools and test equipment
VAG1551 Scan Tool (ST) with VAG1551/3
adapter cable

Note:
VAG1552 can also be used, but there is no print-
out capability.

Requirements
Fuses for engine electronics OK
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Battery Positive Voltage (B+) OK (at least 11
volts)
Engine and transmission GND connections
OK Electrical Wiring Diagrams,
Troubleshooting & Component Locations
binder

Fuel pump relay OK
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01-9

Connecting

Notes:
Scan tool operating instructions - Locate Data Link Connector (DLC), under driver's knee bar to left of
steering wheel.
- Connect VAG1551 Scan Tool (ST) with VAG1551/3 adapter cable to
DLC.
- Switch ignition on, or start engine, depending on function to be
selected ( page 01
-5 ).
If scan tool displays do not appear as indicated:If "Error in communication link" is displayed, disconnect adapter cable
at scan tool, reconnect, and repeat procedure.
- Operate scan tool and advance through program sequence by
following display:
- Press button -1- to select "Rapid data transfer" operating mode 01.
- Press buttons -0- and -1- to insert "Engine Electronics" address word
01, and press -Q- button to confirm input.
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01-10

4D0907551A 2.8L V6/5V MOTR HS D01 Coding 06051
WSC 00000

Indicated on display (ECM identification and coding, example)
4D0 _ _
_ Engine Control Module (ECM) Part No.
2.8 L Engine displacement
V6/5V Engine type:
V-engine, 6-cylinder, 5-valve
MOTR Motronic
HS
AT Manual transmission
Automatic transmission
D.. ECM software version
Coding ECM coding
Coding variations page 01
-14

WSC
12345 Plant number: indicates where VAG1551 scan tool was used
for last coding and/or adaptation (as long as factory coding
has not been changed, WSC 00000 is displayed)
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01-11

Notes:
If the ECM version that corresponds to the
vehicle is not displayed, replace ECM page
01
-68
. Incorrect ECM coding leads to:

Performance problems (e.g. jerky shifting,
abrupt load changes, etc.)
Increased fuel consumption
Elevated exhaust gas values
Reduction in transmission service life
Storage of non-existent malfunctions in DTC
memory
Necessary functions not being carried out
(oxygen sensor control, actuation of EVAP
canister system, etc.)

-
Press button to advance through program
sequence.
Rapid data transfer
HELP
Select function XX

Indicated on display
- Continue as specified in procedures for specific OBD functions.
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