display AUDI A4 2000 B5 / 1.G AWM Engine Motronic Injection System Servicing Workshop Manual

24-22

Engine Control Module (ECM), replacing


Special Tools and Equipment

Removing
VAS5051 with VAG5051/1
- Connect VAS5051 tester Page 01
-7 and select vehicle system "01 -
Engine electronics". Ignition must remain switched on for this.

VAS5051 tester display will indicate the control module identification and
coding -2-.
- Always allow display of control module identification first and print it
out.
- Compare coding with coding versions Page 01
-73
.
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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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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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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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If idle speed is too high or low and there are
no DTCs in DTC memory, the following tests
(marked with dots) must be performed:

Check for false air in intake air system
Page 24
-68
.

Check throttle valve control module Page 24
-124
.

Evaporative Emission (EVAP) canister purge
regulator valve always open, checking
Page 24
-114
.

Perform adaptation of throttle valve control
module Page 24
-125
.
Significance of 5 digit indication of display group 056 x
x
x
x
x
Display field 4
0 A/C compressor: 0 = A/C compressor off; 1 = A/C compressor on
0 Manual transmission: Indication always 0
Driving mode for automatic transmission: 0 = selector lever in P or N; 1 = selector lever in 2/3/4/D/R
0 Indication always 0
0 Indication always 0
0 Indication always 0
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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 Page 01
-7 and
select vehicle system "01 - Engine electronics".
Engine must run at idle for this.

Display on VAS5051:
- In selection -1-, click on the diagnostic function "04 - Basic setting".
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Display on VAS5051:
1 - Enter display group Max. input value = 255
- Select function "002" in button field -2- for "display group number 002"
and press Q button to confirm input.

Display on VAS5051:
- Check specified values for load detection in display fields -3- and -4-.
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Display fields

1 2 3 4
Display group 002: Air mass taken in with engine at idle and operating temperature
Display xxx /min xxx %
xx.x ms
xxx.x g/s
Indicated Engine speed (RPM) Load
mean injection time
Air mass
Specified value FWD: 740 to 860 RPM
AWD: 820 to 880 RPM 15 to 35 %
1.0 to 4.0 ms
2.0 to 4.5 g/s
Note --- ---
If specified value is not obtained: Evaluation Page 24
-63

If specified value is obtained:

-
End function "04 - Basic setting" by pressing
button.
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Evaluation display group 002 Display field:
3
Possible cause
Corrective action
less than 1.0
ms
Smaller values are only possible when driving in
deceleration mode
larger than
4.0 ms Engine under load due to power accessories.- Reduce load (A/C system/power
steering/generator)

Poor idle (does not run on all cylinders)- Check spark plugs.
- Check fuel injectors Page 24
-37
.


Throttle valve control module - J338- faulty- Check throttle valve control module
Page 24
-124

Display field:
4
Possible cause
Corrective action
smaller than
2.0 g/s
large false air mass between intake manifold and Mass Air
Flow (MAF) sensor
Voltage supply of Mass Air Flow (MAF) sensor or wire
connections to Engine Control Module (ECM) - Check intake system for leaks (false air)
Page 24
-68
.
- Check voltage supply and wire
connections Page 24
-64

larger than
4.5 g/s
Engine under load due to power accessories.- Reduce load (A/C system/power
steering/generator)

Voltage supply of Mass Air Flow (MAF) sensor or wire
connections to Engine Control Module (ECM) - Check voltage supply and wire
connections Page 24
-64

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Display on VAS5051:
- Select diagnostic function "08 - Read Measuring Value Block" in
selection -1-.

Display on VAS5051:
1 - Enter display group Max. input value = 255
- Select function "001" in button field -2- for "display group number 001"
and press Q button to confirm input.
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