Air Injection Control (AIS)

In order for the catalytic converter to reach operating temperature as soon as possible, air from an air pump (125) is injected into the exhaust gas directly behind the exhaust valves. The electronic clutch of the air injection is engaged by the LH control unit (N3/3) via the air injection relay (K17). At the same time, the air injection pump switch-over valve is energized which applies vacuum to the air injection shut-off valve (126).

Air injection occurs after starting the engine at a coolant temperature between 10 °C (50 °F) and 44 °C (111 °F), an engine speed of less than 2750 RPM and below a specified air mass. The air is injected for a maximum of 155 seconds depending on coolant temperature. The oxygen sensor control in inactive during air injection.