Idle and (IAC) System

The idle-up system should operate when the running lights, heater fan, cooling fan, or rear defogger are put into operation. If idle-up actuator fails to operate when any of these accessories are switched on, check if proper signal is sent to ECM as follows:
1. Disconnect ECM connector.
2. Switch on ignition without starting engine.

Fig. 24 Idle-Up Compensator Signal Test Connections:

3. Connect voltmeter between terminal 7 and body (ground), Fig. 24. Activate each component as mentioned previously. If voltmeter reads 11--14 volts as each component is activated, the idle-up signal is being sent to the ECM. If reading of 11--14 volts is not obtained, circuit is making poor contact or is open. Correct as necessary.
4. Reconnect ECM connector securely.