Outline Of Diagnosis

When cold, the abnormality in the control of target engine speed increase is detected. (DTC P050A) 

Judge as NG if the idle speed diagnosis is NG.

<Idle speed diagnosis>

Judge as NG when actual engine speed is not close to target engine speed at cold start.

Detect malfunctions of the catalyst advanced idling retard angle control. (DTC P050B) 

Judge as NG when ECM is not controlling the angle properly during catalyst advanced idling retard angle control.

<Final ignition timing diagnosis>

Judge as NG when actual retard amount is under the specified value at cold start.