Secondary Air System Monitoring

GENERAL DESCRIPTION

At cold start the secondary air pump and valve are switched on for their normal operating function. The secondary air delivered into the exhaust gas is causing a lean mixture indicated by the output voltage of the oxygen sensor.

Any time the oxygen sensor indicates a lean mixture within the maximum time for monitoring, a counter is incremented by "one" up to a predetermined value.

This fixed limit corresponds to the minimum amount of secondary air (low-flow-limit-check).





MONITORING STRUCTURE