1999 AUDI TT relay

26-30


Function:

In the cold start phase, the ECM -2- activates
the secondary air pump -12- via the relay for
secondary air pump -1-. Air is supplied to the
combination valve for Secondary Air Injection
(AIR) -10-.
The Secondary Air Injection (AIR) valve -3- is
activated in parallel, which allows the vacuum to
reach the combination valve for Secondary Air
Injection (AIR) -10- and the vacuum diaphragm
for charge air pressure regulation -7-. The
combination valve for Secondary Air Injection
(AIR) thereby opens the path for secondary air
to the exhaust channels of the cylinder head.
Pa
ge 2 of 16 Secondar
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ystem, checkin
g (en
gine code ATW
)
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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26-31



To prevent unnecessary heating, the secondary
air is diverted past the turbocharger -7-. For
this, the charge air pressureregulation pressure
unit opens the charge air pressure valve. The
pressure unit, designed as a double reservoir,
has a vacuum connection for this on the intake
side.
1 -
Secondary Air Injection (AIR) pump relay -
J299-
2 -
Motronic Engine Control Module (ECM) -
J220-
3 -
Secondary Air Injection (AIR) solenoid
valve -N112-
4 -
Intake manifold
5 -
Check valve
Installation position (light/dark side): Arrow
points in direction of flow, as shown
Pa
ge 3 of 16 Secondar
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ystem, checkin
g (en
gine code ATW
)
11/18/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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26-36


Electrical Wiring Diagrams, Troubleshooting & Component Locations
Repair Manual, Fuel Supply System, Repair Group 20

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 VAG1527B voltage tester between terminals 1 and 2 using
test leads from VAG1594A.
- Connect VAG1551 scan tool.
- Initiate output Diagnostic Test Mode (DTM) and activate Secondary Air
Injection (AIR) solenoid valve -N112-.
Output Diagnostic Test Mode Secondary Air Inj. Solenoid Valve -N112

Indicated on display

LED must blink.
Pa
ge 8 of 16 Secondar
y air s
ystem, checkin
g (en
gine code ATW
)
11/18/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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pair&id=AUDI.B5.GE02.26.2

26-38


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

Special tools and equipment

VAG1526A
VAG1527B
VAG1594A
VAG1598/31
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26-39
Installation location:

Repair Manual, 1.8 Liter 4-Cyl. 5V Turbo Fuel
Injection & Ignition, Repair Group 24
- Initiate output Diagnostic Test Mode (DTM) and
activate Secondary Air Injection (AIR) pump
relay -J299-.

A - If relay does not trigger:
B - If relay triggers, but Secondary Air Injection (AIR) pump does not run:
The Secondary Air Injection (AIR) pump relay (in 3-socket relay
carrier in the E-box, at left in plenum chamber, position 2) must
trigger and the Secondary Air Injection (AIR) pump motor -V101-
must run in intervals
- Check voltage supply of Secondary Air Injection (AIR) relay Page
26
-40
.
- Checking activation of Secondary Air Injection (AIR) relay Page 26
-
42
.
- Check voltage supply for Secondary Air Injection (AIR) pump Page
26
-43
.
Pa
ge 11 of 16 Secondar
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11/18/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE02.26.2

26-40

Checking voltage supply of Secondary Air
Injection (AIR) pump relay

- Remove Secondary Air Injection (AIR) pump
relay.

If specified value is not obtained: - Connect multimeter for voltage measurement as follows.3-socket relay carrier in E-box, plenum
chamber, position 2
terminal
Measure to

8 Engine Ground
(GND)

Specified value: approx. battery voltage
- Perform the following tests marked with dots:

Electrical Wiring Diagrams, Troubleshooting & Component Locations Check fuse S130 (40 A) in 3-socket relay carrier in E-Box, plenum
chamber, position 7. Check wire connection from Battery (B+) (terminal 30) to Secondary
Air Injection (AIR) pump relay -J299- (in 3-socket relay carrier in E-
Box, plenum chamber, position 2) for open circuit.
Pa
ge 12 of 16 Secondar
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ystem, checkin
g (en
gine code ATW
)
11/18/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE02.26.2

26-41


If specified value is not obtained: - Connect multimeter for voltage measurement as follows.3-socket relay carrier in E-box, plenum
chamber, position 2
terminal
Measure to

4 Engine Ground
(GND)
- Operate starter briefly.

Specified value: approx. battery voltage
- Perform the following tests marked with dots:

Electrical Wiring Diagrams, Troubleshooting & Component Locations Check fuse S234 (in fuse holder, position 34). Check wire connection from Secondary Air Injection (AIR) pump relay
-J299- (in 3-socket relay carrier in E-box, plenum chamber) via fuse
S234 (in fuse holder, position 34) to Fuel Pump (FP) relay for open
circuit:
Pa
ge 13 of 16 Secondar
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ystem, checkin
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gine code ATW
)
11/18/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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pair&id=AUDI.B5.GE02.26.2

26-42

Checking activation of the Secondary Air
Injection (AIR) pump relay

- Switch ignition off.

- Remove Secondary Air Injection (AIR) pump
relay.

If LED does not blink: - Connect VAG1527B voltage tester as follows:3-socket relay carrier in E-box, plenum
chamber, position 2
terminal
Measure to

6 Engine Ground
(GND)
- Initiate output Diagnostic Test Mode (DTM) and activate Secondary Air
Injection (AIR) pump relay -J299-.

LED must blink.
- Switch ignition off.
- Connect VAG1598/31 test box at wiring harness to ECM, do not
connect ECM.
Pa
ge 14 of 16 Secondar
y air s
ystem, checkin
g (en
gine code ATW
)
11/18/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE02.26.2