Trooper (2 Door) V6-3165cc 3.2L DOHC (6VD1) (1992)
Idle Speed/Throttle Actuator - Electronic: Testing and Inspection
Chart C-2C IAC System Check
Circuit Description
The engine control module (ECM) controls engine idle speed with idler air control (IAC) valve. To increase idle speed, the ECM retracts the IAC valve
pintle away from its seat, allowing more air to bypass the throttle bore. To decrease idle speed, it extends the IAC valve pintle towards its seat, reducing
bypass air flow. A "Scan tool" will read the ECM commands to the IAC valve in counts. Higher counts indicate more air bypass (higher idle). Lower
counts indicate less air is allowed to bypass (lower idle).
Test Description
Number below refer to circled numbers on the diagnostic chart.
1.
The IAC tester is used to extend and retract the IAC valve. Valve movement is verified by a engine speed change. If no change in engine speed
occurs, the valve can be retested when removed from the throttle body.