Disconnect the electrical harness to the IAC valve while the engine is idling.
Check to see that the rpm drops.
Connect the IAC valve connector and check to see that engine rpm resumes
its original speed.
NOTE: Disconnecting the harness causes a change in engine
rpm when the engine is cold. However, when the engine is warm, it causes
a smaller change, or almost no change at all.
Stop the engine, then disconnect the electrical harness from the IAC valve.
Turn the ignition switch to the ON position.
Using a voltmeter, measure the voltage across power terminal BW on
the IAC valve connector and ground. Voltmeter should read 10 volts. If the
voltage obtained is less than specified, check the harness.
Turn the ignition switch to the OFF position. Using an
ohmmeter, measure the resistance between each terminal of the connector on
the IAC valve. The ohmmeter should read 7.3–13 ohms at −4°F–176°F
(−20°C–80°C). If specifications are not as specified,
replace the IAC valve.
Using an ohmmeter, measure the insulation resistance between each terminal
of the connector on the IAC valve and ground. The ohmmeter should read 1 mega-ohm.
If specifications are not as specified, replace the IAC valve.
Connect the IAC valve harness, then disconnect the control unit electrical
harness.
Turn the ignition switch to the ON position. Using a voltmeter,
measure the voltage between terminal 45 (GR) of the control
unit harness and ground. Voltmeter should read 10 volts. If specifications
are not as specified, check the harness between the IAC valve and the control
unit.
Turn the ignition switch to the OFF position, then connect
the control unit harness.
Monitor the voltage across terminal 45 (GR) on the control
unit harness and ground, when the ignition switch is turned to the ON position.
Voltmeter should read 1 volt for approximately 1 minute after the ignition
switch is turned ON and 10 volts after 1 minute. If specifications
are not as specified, check for poor contact of the terminal or a faulty control
unit.
Turn the ignition switch to the OFF position, then disconnect
the IAC valve hose.
Turn the ignition switch to the ON position. Look through
the open end of the pipe (from which the air control pipe was disconnected)
and check that the valve moves from the fully closed position to the fully
opened position, 1 minute after the ignition switch is turned to the ON position.