1999 AUDI A4 AWM Engine Motronic Injection System Servicing Workshop Manual

24-23

- Switch ignition off.

- Pull off rubber seal of plenum chamber cover in direction of arrow.
- Remove cover -1- toward front.

- Remove Heater Core E-box cover (arrows).
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24-24


- Using a screwdriver, carefully pry off retaining bracket (arrow).

Note:
Adaptation values are erased when connector is disconnected from the
Engine Control Module (ECM), DTC memory content remains intact. - Disengage connector catches (arrows) and disconnect harness
connectors -1- and -2- from control module.
- Remove Engine Control Module (ECM).
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24-25

Installing
Installation is reverse of removal, noting the
following:

After connecting new Engine Control Module
(ECM), the following work steps must be
performed:

- Activate Engine Control Module (ECM) in
"Guided Troubleshooting" below diagnostic
object "Engine Control Module (ECM),
replacing".
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24-26

Idle speed (RPM), checking


Special Tools and Equipment

Test requirements:
VAS5051 with VAG5051/1Exhaus system free of leaks. Coolant Temperature at least 80 C. Electrical consumers switched off (radiator fan must NOT run during
test). A/C switched off. No pressure gauge connected. Vehicles with automatic transmission Selector lever in P or N.
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24-27

Notes:

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
-12
. 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.
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Display on VAS5051:
- In selection -1-, click on the diagnostic function "04 - Basic setting".

Display on VAS5051:
1 - Enter display group Max. input value = 255
- Select function "056" in button field -2- for "display group number 056"
and press Q button to confirm input.
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24-29


Display on VAS5051:
- Check whether the engine speed in display field -1 (actual engine
speed) is within the permissible specified 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: 760 to 880 RPM FWD: 800 RPM
AWD: 820 RPM x.x % 0 0 0 0 0
Note
If specified value is not obtained
Page 24
-31

Significance of numbers
Page 24
-31
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24-30

Notes:

Engine speed in display field 1 (actual engine
speed) is the current engine speed.
Engine speed in display field 2 (specified
engine speed) is a theoretical engine speed
calculated by the ECM.
At idle, the ECM always attempts to adapt the
engine speed (actual) to the specified engine
speed (specified).
This means that the engine speed (actual) must
always approximately match the engine speed
(specified) at idle.
Display fields 3 and 4 provide information, but
are not relevant for checking idle speed.

Display on VAS5051:
If specified value is obtained:
If specified value is not obtained: -
End function "04 - Basic setting" by pressing button.- Check DTC memory again Page 01
-12
.
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