A GM vehicle with high idle speed is being diagnosed. Technician A says if the IAC counts show a value of 0, a vacuum leak is a possible cause. Technician B says if the IAC counts show a value of 0, the PCM may not be able to control the IAC. Who is correct?
A)Technician A only
B)Technician B only
C)Both A and B
D)Neither A nor B

Question

Quizplus · Accepted Answer

If the IAC counts show a value of 0, it indicates that the PCM is trying to close the IAC to reduce idle speed, which could be due to a vacuum leak (Technician A) or a failure in the PCM's ability to control the IAC (Technician B).

A GM Vehicle with High Idle Speed Is Being Diagnosed