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

24-63
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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Voltage supply for Mass Air Flow (MAF)
sensor, checking

Test requirements:

Fuse for Mass Air Flow (MAF) sensor OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations

Fuel Pump (FP) relay OK; checking Page 24
-52
.

Note:
Voltage is supplied to Mass Air Flow (MAF)
sensor from Fuel Pump (FP) relay.

- Disconnect connector from Mass Air Flow (MAF)
sensor.

- Connect multimeter for voltage measurement as follows.Harness connector
Terminal
Measure to
2 Engine Ground (GND)
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- Operate starter briefly (engine can also start).

Specification: approx. battery voltage
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If specified value is not obtained:

- Check wire connection from terminal 2 of
connector to Fuel Pump (FP) relay via fuse for
open circuit and short circuit to Ground (GND):

Electrical Wiring Diagrams, Troubleshooting &
Component Locations
- Repair open circuit or short circuit if
necessary.

Note:
Ground (GND) from the ECM is present at terminal 3 of connector.
If specified value is not obtained: - Connect multimeter to terminal 2 and terminal 3 of connector for
voltage measurement.
- Operate starter briefly (engine can also start).

Specification: approx. battery voltage
- Check wire connections Page 24
-67
.
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If specified value is not obtained: - Connect multimeter to terminal 3 and terminal 4 of connector for
voltage measurement.

Specification: about 5 V
- Check wire connections Page 24
-67
.
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Check wire connections for Mass Air Flow
(MF) sensor

Note:
Signal wire is also checked during wire test.

- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

If wire connection is OK: - Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
3 27
4 53
5 29
- Repair open circuit or short circuit if necessary.
- Also check all wires for short circuit to each other.
- Replace Mass Air Flow (MAF) sensor -G70-.
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Intake system, checking for leaks
(unmetered air)


Special tools and equipment

Notes:
Test sequence
VAS5051 with VAG5051/1Engine leak detection spray G 001 800 A1The negative pressure in the intake system sucks in the leak detection
spray with the unmetered air. Leak detection spray decreases ignition
quality and performance of the fuel mixture. This causes a reduction in
engine speed and a sharp increase of CO content. It is absolutely necessary to follow the safety precautions listed on the
can.
- Connect VAS5051 tester Page 01
-7 and select vehicle system "01 -
Engine electronics". Engine must run at idle for this.
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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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Display on VAS5051:
If engine speed decreases: - Make note of engine speed in display field -1.
- Spray intake system parts with engine leak detection spray in a
systematic manner.
- Check sprayed part of intake system for leaks, and eliminate the error.
-
Press "08 - erase DTC memory" to end function -button.- Select "06 - End Output"
- Switch ignition off.
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