Idle Speed Control Cold-Start Monitoring

IDLE SPEED CONTROL COLD-START MONITORING

Cold start idle speed control - Rationality diagnosis

General Description
This diagnosis detects the stability of the idle speed. If the commanded idle speed and the actual idle speed is not within a calibrate able value, above or below commanded, in spite of an activated idle speed controller the idle speed is considered to be out of range.

Due to different engine operating characteristics a cold start diagnosis is performed by using limits depending on the temperature of cooling water and time after start.

If the above failure conditions are detected, the appropriate DTC will be stored.

Within this diagnosis is also defined an interface between the idle speed cold-start monitor and the 'Rate-Based Monitoring statistics'.

Flowchart: Cold start idle speed control - Rationality diagnosis