Cutlass Supreme FWD V6-189 3.1L (1989)
CHART C-2B
Test Description:
Numbers below refer to circled numbers on the diagnostic chart.
1.
Continue with test even if engine will not idle. If idle is too low, "Scan" will display 80 or more counts, or steps. If idle is high it will display "0"
counts. Occasionally an erratic or unstable idle may occur. Engine speed may vary 200 rpm or more up and down. Disconnect IAC. If the
condition is unchanged, the IAC is not at fault. There is a system problem.
2.
Be sure to disconnect the IAC valve prior to this test. The test light will confirm the ECM signals by a steady or flashing light on all circuits.
3.
IAC wiring is routed from the ECM through a mini harness. Faulty connection or shorted wires could result in poor IAC operation.
4.
This test checks for an internal short between the IAC coils.
