1996 AUDI A4 check engine

24-2

CAUTION!

To operate the engine at starter speed
without actually starting it (for example, in
order to test compression), unplug the
connectors from the output stages for the
ignition coils and also the connectors on the
injectors.
During some of the tests the control module
may identify and record malfunctions. The
DTC memory should therefore be checked
and (if necessary) erased after completing
the tests and any repair work that may be
required. After erasing DTC memory
generate new readiness code Page 01
-
105
.

Always switch off the ignition before
cleaning the engine.
Always switch off the ignition before
connecting or disconnecting the battery,
otherwise the engine control module may be
damaged.
Be sure of proper radio code (for vehicles
equipped with coded anti-theft radio)

Be sure the battery negative (-) cable is
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24-20

Wiring and component check with
VAG1598/31 test box


Notes:

The VAG1598/31 test box is designed so it can
be simultaneously connected to the control
module wiring harness and to the control
module itself.
This has the advantage of enabling the engine
management system to remain fully operational
even with the test box connected (for example,
when testing signals while the engine is
running).
The instructions for performing the individual
tests indicate whether or not the engine control
module itself also needs to be connected to the
test box.
Use the hand multimeter Fluke 83 (or
equivalent) or the multimeter VAG1715 and the
diode test lamp VAG1527 for the checks.
To connect the testers to VAG1598/31 test box,
always use the adapter leads from VAG1594 A
connector test kit.

Required special tools and test equipment
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24-22


After installing the engine control module, carry out the following
operation
Note:
At the first learning (adaptation) phase during the "Engine-Basic Setting"
the engine might run a little rough at idle and bucks/jerks a little while
driving. - Connect VAG1598/31 test box to wiring harness connector. Also
connect the Ground (GND) clamp from test box to Ground (GND). The
instructions for performing the individual tests indicate whether or not
the engine control module itself also needs to be connected to the test
box.
- Carry out test as described in the relevant repair instructions.
- Check DTC memory and erase if necessary Page 01
-15
.
- Generate new readiness code Page 01
-105
.
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24-23

Procedure after interrupting voltage
supply


Note:
At the first learning (adaptation) phase during the
"Engine-Basic Setting" the engine might run a
little rough at idle and bucks/jerks a little while
driving.

Required special tools and test equipment

Work procedure
Carry out the following work after the voltage was interrupted:
VAS 5051 with VAS 5051/1
orVAG1551 with VAG1551/3B
- Check DTC memory and erase if necessary Page 01
-15
.
- Generate new readiness code Page 01
-105
.
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24-26

Important Note:
After installing new engine control module, carry
out the following operations:
- Check DTC memory and erase if necessary
Page 01
-15
.
- Perform adaptation of Throttle Valve Control
Module -J338 Page 24
-146
.
- Observe notes for coding new engine control
module Page 01
-93
.
- On vehicles with cruise control (recognizable at
steering column switch), activate cruise control
function in the engine control module.

Repair Manual, Electrical Equipment, Repair
Group 01

- On vehicles with automatic transmission carry
out adaptation for Kick-Down switch Page 24
-
166
.
- Generate readiness code Page 01
-105
.
- Perform adaptation of immobilizer to engine
control module

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24-27

Idle speed, checking


Test conditions

No leaks in exhaust system
Coolant temperature at least 80 C

Electrical consumers switched off (radiator
fan must not run during the check)
A/C switched off
Pressure gauge not connected
Selector lever in position P or N (vehicles
with automatic transmission)

Checking idle speed

Notes:
The idle speed cannot be adjusted.
The idle speed is tested during the basic setting
of the engine.
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24-28

- Check DTC memory Page 01
-15
. The DTC
memory must be clear. If necessary, repair any
malfunctions and erase the DTC memory.
Switch off the engine, then start up again. Take
vehicle for a test drive and check DTC memory
again to make sure it is clear.

- Run engine at idle speed.

CAUTION!

The electric radiator fan should not be
running. Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -4- to select function "Basic Setting" and confirm
entry with -Q- button.
Basic settin
g
Input displa
y group number XXX

Indicated on display
- Press buttons -0- -5- and -6- to select "Display group number 056" and
confirm entry with -Q- button.
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24-29
Notes:
System in Basic Setting 56
1
2
3
4

Indicated on display: (1 - 4 display zones) - Check whether the engine speed shown in display field 1 (actual
engine speed) is within the specified tolerance range (750 - 850 RPM).

Display fields

1 2 3 4
Display Group 056: Idle speed stabilization with engine idling at operating temperature
Display
xxx RPM
xxx RPM x.x % xxxxxxx
Indicates
Engine speed (actual)
Engine speed
(specified) Idling speed control-
torque change Operating conditions
Specified
value 750 -850 RPM
800 RPM x.x % 0 0 0 0 0
Note
If readout does not match
Specified value Page 24
-31

Relevance of figures
Page 24
-32

The value shown in display field 1 is the actual engine speed.
The value shown in display field 2 (specified engine speed) is a theoretical value calculated by the engine control module.
See note on next page:
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