check AUDI A4 1995 B5 / 1.G APB Engine Secondary Air System Workshop Manual

26-32


Function:

In the cold start phase, the ECM -4- activates
the secondary air pump -2- via the relay for
secondary air pump -3-. Air reaches the
combination valves for Secondary Air Injection
(AIR) -5- and -9-.
The Secondary Air Injection (AIR) valve -6- is
activated in parallel, which allows the vacuum to
reach the combination valves for Secondary Air
Injection (AIR) -5- and -9-. The appropriate
combination valve for Secondary Air Injection
(AIR) thereby opens the path for secondary air
to the exhaust channels of the cylinder head.
1 -
Secondary Air Injection (AIR) pump relay -
J299-
Removing and installing Page 26
-37
checking Page 26
-45
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2 -
Motronic Engine Control Module (ECM) -
J220-
3 -
Combination valve for secondary air
injection (AIR)
4 -
Secondary Air Injection (AIR) solenoid
valve -N112-
Installation position Fig. 1
5 -
Secondary Air Injection (AIR) pump motor
-V101-
Installation position Fig. 2
6 -
Check valve
Installation position (light/dark side): Arrow
points in direction of flow, as shown in
figure.
7 -
To Intake manifold
8 -
Combination valve for secondary air
injection (AIR)
9 -
Vacuum reservoir Installation location: Under wheel housing
liner in wheel housing
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Secondary Air Injection (AIR) solenoid
valve -N112-, checking

Special tools and equipment

VAG 1526A
VAG 1527B
VAG 1594A
VAG 1598/31
VAS 5051
- or
VAG 1551 with VAG 1551/3A
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Installation location Installation locations-
Overview
Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 24


Test requirement:

Output Diagnostic Test Mode (DTM)
performed

Checking internal resistance

- Disconnect harness connector from Secondary
Air Injection (AIR) valve -N112-.

- Connect multimeter at valve for resistance measurement.

Specified value: 25 ... 35
- If specified value is not obtained, replace Secondary Air Injection (AIR)
solenoid valve -N112-.
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26-41

Checking voltage supply

- Disconnect connector from Secondary Air
Injection (AIR) solenoid valve -N112-.

If LED does not light: - Connect VAG 1527B voltage tester as follows:Harness connector terminal
Measure to
1 Engine Ground (GND)
- Operate starter briefly.

LED must light.
- Perform following tests marked with dots:

Check fuse -S234- (in fuse holder, position 34).
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Electrical Wiring Diagrams, Troubleshooting & Component Locations
Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel Injection & Ignition,
Engine Code(s): APB, Repair Group 24

Checking activation
Check wire connection from terminal 1 of connector via fuse -S234-
(in fuse holder, socket 34) to Fuel Pump (FP) relay for open circuit: Check Fuel Pump (FP) relay.

- Connect VAG 1527B voltage tester between terminal 1 and 2.
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26-43

- Initiate output Diagnostic Test Mode (DTM) and
activate Secondary Air Injection (AIR) solenoid
valve -N112

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 01

Output Diagnostic Test Mode Secondary. air. inj. solenoid valve -N112

Indicated on display
If LED does not blink or if it remains constantly lit:
Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel Injection & Ignition, Engine Code(s): APB, Repair Group 24

LED must blink.
- Connect VAG 1598/31 test box at wiring harness to ECM, do not
connect ECM.

- Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+: Harness connector terminal
VAG 1598/31 test box
Bushing
2 44
- Repair open circuit or short circuit if necessary.
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26-45


Secondary Air Injection (AIR) pump relay -
J299- and activation, checking

Special tools and equipment

VAG 1526A
VAG 1527B
VAG 1594A
VAG 1598/31
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26-46
Installation location Installation locations-
Overview.
Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 24


Test sequence

- Initiate output Diagnostic Test Mode (DTM) and
activate Secondary Air Injection (AIR) pump
relay -J299-

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 01


A - If relay does not trigger:
The Secondary Air Injection (AIR) pump relay (in 3-socket relay
carrier in the E-box, at left in plenum chamber, position 2) must
engage and the Secondary Air Injection (AIR) pump motor -V101-
must run in intervals
- Check voltage supply of Secondary Air Injection (AIR) pump relay
Page 26
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.
-
Check activation of Secondary Air Injection (AIR) pump relay Page
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B - If relay triggers, but Secondary Air Injection (AIR) pump does not run: 26
-49
.
- Check voltage supply of Secondary Air Injection (AIR) pump motor
Page 26
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