Corsica L4-121 2.0L (1988)
Fig. 037 Chart C-2C Idle Air Control
Test Description:
Step numbers refer to step numbers on diagnostic chart.
1.
Continue with test, even if engine will not idle, If idle is to low, "Scan" will display 80 or more counts, or steps. If idle is high, it will display "O"
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.
2.
When the engine was stopped, the IAC Valve retracted (more air) to a fixed "Park" position for increased air flow and idle speed during the next
engine start. A "Scan" will display 100 or more counts.
3.
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.
4.
There is a remote possibility that one of the CKTs is shorted to voltage, which would have been indicated by a steady light. Disconnect ECM and
turn the ignition "ON" and probe terminals to check for this condition.
Diagnostic Aids:
