1995 AUDI A3 set

24-19

Wiring and component testing using
VAG1598/31 test box


Note:

VAG1598/31 test box is designed so that it can
be simultaneously connected to the wiring
harness at the Engine Control Module (ECM)
and also to the ECM itself.
This is advantageous because electronic
engine control remains fully functional (e.g.
measurement of signals with engine running)
when the test box is attached.
Relevant test procedures note whether Engine
Control Module (ECM) should also be
connected to the test box or not.
Always use VAG1594A connector test kit to
attach measurement devices (e.g. VAG1527B
voltage tester, VAG1526 multimeter etc.).

WARNING!

To avoid damaging electronic components,
set measuring range before connecting test
leads and observe all test requirements.
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24-29

Note:

Idle speed cannot be adjusted.
Idle speed is checked during basic setting of
the engine.
During basic setting, the Evaporative Emission
(EVAP) canister purge regulator valve (EVAP
valve -N80-) is closed and the A/C compressor
is switched off

Test sequence

- Check DTC memory Page 01
-16
. There must
not be any DTCs stored, repair malfunctions if
necessary, erase DTC memory, switch engine
off and start again, road test vehicle and check
DTC memory again as a control measure.

- Let engine continue to run at idle.

WARNING!

The electric fan for the radiator must not be
running. Rapid data transfer
HELP
Select function XX

When indicated on display
-
Press buttons -0- and -4- to select "Initiate basic setting" and press -Q-
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24-30

Basic Settin
g
Q
Enter display group number XXX

When indicated on display
- Press buttons -0-, -5- and -6- to select "display group number 056" and
press -Q- button to confirm input.
System in basic setting 56
1
2
3
4

When indicated on display
- Check whether the engine speed in display field 1 (actual engine speed) is
within tolerated range.

Display fields

1 2 3 4
Display group 056: Idle stabilization at operating temperature
Display
xxx /min
xxx /min x.x % X X X X X
Indicated
Engine speed (actual)
Engine speed
(specified) Idle control
Torque
change Operating conditions
Specified
value FWD: 740 to 860 RPM
AWD: 800 to 920 RPM FWD: 800 RPM
AWD: 860 RPM x.x % 0 0 0 0 0
Note
If specified value is not obtained
Page 24
-32

Significance of numbers
Page 24
-32
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24-47

- Disconnect fuel distributor with injectors from
intake plenum and set aside in rear of engine
compartment on a clean cloth.

WARNING!

Fuel system is under pressure! Before
opening system, place rags around the
connection point. Then release pressure by
carefully loosening connection.

- Disengage retaining clip and remove fuel
injector.

Note:
Fuel lines must be removed before replacing fuel
distributor.
Installation is reverse of removal, noting the
following:

Remove O-rings at all opened connections.
(Never remove plastic cap from valve head
to replace front O-ring - pry O-ring off over
plastic cap).
Lightly lubricate O-rings with clean engine
oil.
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24-61
Component location Overview of component
locations Page 24
-5

Test requirements:

Coolant Temperature at least 80 C.

Electrical consumers switched off (radiator
fan must NOT run during test).
A/C switched off.

Checking function

- Connect VAS5051 tester or VAG1551 scan tool
and select control module for engine electronics
using "address word" 01 Page 01
-10
. Engine
must run at idle.
Rapid data transfer
HELP
Select function XX

When indicated on display
- Press buttons -0- and -4- to select "Initiate basic setting" and press -Q-
button to confirm input.
Basic Setting
Q
Enter displa
y group number XXX

When indicated on display
- Press buttons -0-, -0- and -2- to select "display group number 002" and
press -Q- button to confirm input. When indicated on display
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System in basic setting 2
1
2
3
4

- Check specified values for load detection.
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pair&id=AUDI.B5.FU06.24.1