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.