Air Injection: Service and Repair

Secondary air system, overview
The secondary air system is designed to enable catalytic converter to heat up and reach its operating temperature more quickly after a cold start.

Principle of operation
Due to extra mixture enrichment during cold-start phase, an increased amount of unburned hydrocarbons is carried in exhaust gas. The secondary air system improves the after burning (oxidation) process in the catalytic converter, and in this way reduces toxic emissions. Heat generated by oxidation accelerates "light off" of catalytic converter and significantly improves exhaust gas quality during warm-up.

Function

^ After a cold start, engine control unit -3- activates secondary air pump -1- via secondary air pump relay -2-, and air is fed to combination valves for secondary air system -4- and -8-.
^ At the same time, the system activates secondary air inlet valve -5-, which supplies vacuum to combination valves -4- and -8-. The relevant combination valve opens a passage for the secondary air system to supply air to exhaust ports in cylinder head.

1 - Secondary Air Injection (AIR) Pump Motor -V101-
^ Location go to Figure 2
2 - Secondary Air Injection (AIR) Pump Relay -J299-
^ Location go to Figure 3.
3 - Engine control unit -J220-
4 - Combination valve for secondary air system (right)
^ Location go to Figure 4.
5 - Secondary Air Injection (AIR) Solenoid Valve -N112-
^ Location go to F4A.
6 - Non-return valve
^ Installation position as shown in illustration. Arrow indicates direction of flow
7 - To intake manifold
8 - Combination valve for secondary air system (left)
^ Location go to Figure 4.
9 -Vacuum reservoir





Figure 1 Location of Secondary Air Injection (AIR) Solenoid Valve -N112-
^ At right front of intake manifold (arrow)





Figure 2 Location of Secondary Air Injection (AIR) Pump Motor -V101-
^ Rear right of engine compartment

1 - Electrical connector for Secondary Air Injection (AIR) Pump Motor -V101-
2 - Air hose to combination valves for secondary air system.





Figure 3 Location of Secondary Air Injection (AIR) Pump Relay - J299-
^ Socket 1 in 3-way relay carrier in electronics box of plenum chamber





Figure 4 Combination valve for secondary air system
^ At rear of cylinder heads

Note: Illustration shows valve on left side.