Grand Prix V6-204 3.4L DOHC (1992)
Chart C-2B, Idle Air Control Valve Circuit Check
Numbers below refer to circled numbers on the diagnostic chart.
1.
The Tech 1 "SCAN" tool rpm control mode is used to extend and retract the IAC valve pintle. the valve should move smoothly within the
specified range. If the idle speed is commanded too low (below 700 rpm) the engine may stall. This is normal and does not necessarily indicate a
problem. Retracting the pintle beyond its normal control range (above 1500 rpm) will cause a delay before the engine speed drops when
commanded low again. This too is normal.
1.
This test the Tech 1 "SCAN" tool to command the controlled idle speed. The PCM commands the IAC valve to obtain the specified idle speed.
The node lights should flash red and green, indicating a good circuit. While the sequence of flashes is not important, if either light fails to flash, or
does not flash red AND green, check the circuits for faults. Look for poor connections, open circuits or shorts to ground.
