Air Injection: Service and Repair

SECONDARY AIR INJECTION SYSTEM, OVERVIEW:

US vehicles Only up to 07.96:

Function:

The Secondary Air Injection System blows in air behind the exhaust valve for 97 seconds during a cold start (+15°C to +35°C engine coolant temperature). This produces an oxygen rich exhaust, causes afterburning and reduces the heat-up time of the catalyst. Activation is via Engine Control Module J169 via the Secondary Air Injection pump relay J299 to Secondary Air Injection valve N112, change-over valve), check valve and combi-valve. In addition to the cold start switch-in phase, the Secondary Air Injection System will be switched on during idle (up to max. 85°C engine coolant temperature) and is checked via On Board Diagnostic II.

NOTES:

^ The system is checked via On Board Diagnostic system:

^ Components marked with ** are checked by Output Diagnostic Test Mode.


SECONDARY AIR INJECTION SYSTEM COMPONENTS, REMOVING AND INSTALLING:



1 - Pressure hose
^ Ensure seated tightly
2 - Check valve
3 - Connecting hose
^ Ensure seated tightly
4 - Combi-valve
^ Checking Testing and Inspection
5 - Gasket
^ Replace
6 - 9 Nm (6 ft lb)
7 - Connecting pipe
8 - 30 Nm (22 ft lb)
9 - Gasket
^ Replace
10 - 10 Nm (7 ft lb)
11 - Secondary Air Injection solenoid valve N112**
^ Checking Testing and Inspection
12 - 2-pin harness connector
13 - Vacuum hose
^ to brake servo check valve connection
14 - Check valve
15 - 40 Nm (30 ft lb)
16 - Bracket
^ Secondary Air Injection pump item -17- and Secondary Air Injection solenoid valve, item -11-
17 - Secondary Air Injection pump**
^ with motor V101
^ Checking Testing and Inspection
18 - Intake hose
^ for Secondary Air Injection pump
19 - To Air Cleaner
^ on intake hose connection
20 - Air channel
^ in cylinder head
21 - Bracket
^ for combi-valve