Secondary Air Injection System Monitoring

Description

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

Any time the oxygen sensor indicates a rich mixture (voltage > a fixed limit) within a predetermined time range and the calculation of the relative secondary air mass is < a defined threshold, the secondary air injection system appears to be faulty.

A correction procedure follows immediately after the secondary air injection system is switched off. The air fuel ratio influence is determined by the deviation of the lambda-controller.

If influence < a fixed threshold, finally a fault will be detected.

If influence > a fixed threshold the results of the diagnosis will be rejected.

As long as a lean mixture (voltage < a fixed limit) is indicated from the front oxygen sensor within a predetermined time range and the correction of air fuel ratio influence (after secondary air injection pump shuts-off) is < a fixed threshold a fault will also be detected.

Monitoring Structure








Drive Cycle Information

P0414 Not Applicable
P1413 Not Applicable
P0412 Not Applicable
P0418 Not Applicable
P0413 Not Applicable
P1414 Not Applicable
P0491 Not Applicable
P0492 Not Applicable