engine AUDI A4 2000 B5 / 1.G AWM Engine Secondary Air System Workshop Manual

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Function

During the cold running phase, the engine
control module -6- actuates the secondary air
injection pump -1- via the secondary air
injection pump relay -5-. Air reaches the
combination valve for the secondary air inlet -3-.
Parallel to this the secondary air inlet valve -8-
is actuated, which allows the vacuum to reach
the combination valve for secondary air inlet -3-.
The combination valve for secondary air inlet
thus allows the secondary air to enter the
exhaust ducts of the cylinder head -9-.
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6 -
Engine Control Module -J220-
7 -
Vacuum reservoir
Location: In front left wheel housing
beneath wheel housing liner
8 -
Secondary Air Injection (AIR) Solenoid
valve -N112- Location Fig. 1
, Page 26
-45
9 -
Cylinder head
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Note:
The illustration shows bottom view of intake pipe. Fig. 1 Installation position Secondary Air Injection (AIR) valve -
N112-
Location: below intake pipe
1 - Recirculating valve for turbocharger -N249- (green connection)
2 - Secondary air injection valve -N112- (brown connection)

Fig. 2 Installation position for Secondary Air Injection (AIR)
Pump motor -V101-
Front right in engine compartment beneath air filter housing
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Fig. 3 Installation position Secondary Air Injection (AIR) Pump
relay -J299-
In E-box in plenum chamber
1 - Engine control module
2 - Secondary air pump relay -J299-
3 - Power supply relay for Motronic -J271-
4 - Fuse S130 for secondary air pump

Fig. 4 Combination valve for secondary air injection
Right rear on cylinder head
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Test requirements:

Vehicle diagnostic, testing and information
system VAS 5051 or VAG 1551 Scan Tool
connected.

Test sequence

Note:
The secondary air injection solenoid valve -
N112- and the wiring connections are monitored
by the engine control module.

- Read out Diagnotic Trouble Code (DTC)
memory of engine control module.
If a DTC relating to the secondary air injection
solenoid valve -N112- is displayed:

Note:
The illustration shows bottom view of intake line. - Remove hoses from secondary air injection solenoid valve -N112- (-2-)
but leave electrical connector plugged in.
Location: below intake line
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Checking power supply

Note:
The power supply for the secondary air injection
solenoid valve -N112- is via the fuel pump relay.

Test requirements:

Fuse for secondary air injection solenoid
valve OK.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder

Fuel pump relay OK.

Repair Manual, 1.8 Liter 4
-Cyl. 5V Turbo Fuel
Injection & Ignition, Engine Code(s): AWM, Repair Group 24


- Disconnect connector from valve.

- Connect voltage tester VAG 1527 B as follows:Connector
Measure to
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contact
1 Engine Ground
- Operate starter briefly.
LED must light up.
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If the LED lamp does not flash or if it lights up
continuously:

- Connect VAG 1598/31 test box to wiring
harness leading to engine control module;
engine control module should not be connected:

Repair Manual, 1.8 Liter 4
-Cyl. 5V Turbo Fuel
Injection & Ignition, Engine Code(s): AWM, Repair Group 24


If the wiring is OK: - Check for open circuit and short to positive or Ground in following
wiring connection: Connector
contact
Test box VAG 1598/31
2 9
- Repair any open/short circuit as necessary.
- Replace engine control module.
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Check voltage supply of secondary air
injection pump relay

- Switch ignition off.

- Remove secondary air injection pump relay.

If specified value is not attained: - Connect multimeter as follows to measure voltage.3-position relay carrier in E-box in plenum chamber,
position 2
Contact
Measure to

8 Engine
Ground
Specified value: approx. battery voltage
- Carry out following tests:

- Check fuse S130 (40 A) in electronics box of plenum chamber, (Pos.
4).
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- Check for open circuit in wiring from battery +
(terminal 30) to fuse S130 for secondary air
injection pump relay (in 3-position in E-box of
plenum chamber, position 2).

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder

If specified value is not attained: - Connect multimeter as follows to measure voltage.3-position relay carrier in E-box in plenum chamber,
position 2
contact
Measure to

4 Engine
Groung
- Operate starter briefly.
Specified value: approx. battery voltage
- Carry out following tests:

Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Check fuse S234 (in fuse box, position 34).
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