Audi Workshop Service and Repair Manuals > A4 Mk2 > Power unit | 4-cylinder engine (5-valve turbo), mechanics | Exhaust system | Secondary air system

Secondary air system - overview

1 -	Secondary air pump motor -V101-

q	Fitting location → Fig.

2 -	Air cleaner

3 -	Combination valve for secondary air system

q	Fitting location → Fig.

4 -	Non-return valve

q	Installation position: as shown in illustration, the arrow points in direction of flow

5 -	Secondary air pump relay -J299-

q	Fitting location → Fig.

6 -	Motronic control unit -J220-

7 -	Vacuum reservoir

q	Fitting location: in front left wheel housing beneath liner

8 -	Secondary air inlet valve -N112-

q	Fitting location → Fig.

9 -	Cylinder head

Fitting location of secondary air inlet valve -N112-

t	Below intake manifold

1 -	Turbocharger air recirculation valve -N249- (green connector)

2 -	Secondary air inlet valve -N112- (brown connector)

Note

t	The illustration shows the intake manifold from below and removed from the engine.

t	Checking secondary air inlet valve -N112- in „Guided Fault Finding“ → Vehicle diagnostic, testing and information system VAS 5051.

Fitting location of secondary air pump motor -V101-

t	At front right in engine compartment below longitudinal member

Note

Checking secondary air pump motor -V101- in „Guided Fault Finding“ → Vehicle diagnostic, testing and information system VAS 5051.

Fitting location of secondary air pump relay -J299-

t	Located in 3-position relay carrier in electronics box in plenum chamber

1 -	Motronic control unit -J220-

2 -	Secondary air pump relay -J299-

3 -	Motronic current supply relay -J271-

4 -	Secondary air pump fuse -S130-

Note

Checking secondary air pump relay -J299- in „Guided Fault Finding“ → Vehicle diagnostic, testing and information system VAS 5051.

Combination valve for secondary air system

t	On rear right of cylinder head.

Note

Checking combination valve for secondary air system for proper operation and leakage → Chapter.

Audi Workshop Service and Repair Manuals