Idle Speed/Throttle Actuator - Electronic: Testing and Inspection

NOTE:
To perform a complete test of AIS motor and its circuitry, refer to appropriate Diagnostic Chart. To test the AIS motor only, exerciser tool (7558) may be used.


TESTING PRECAUTIONS

^ Set the parking brake and block the drive wheels ^ Route all tester cables away from the cooling fans, drive belt, pulleys, and exhaust components

^ Provide proper ventilation while operating the engine

^ Always return the engine idle speed to normal before disconnecting the exerciser tool.


PROCEDURE

MAP Sensor And Connector:

1. With the ignition OFF, disconnect the AIS motor wire connector at throttle body.

Automatic Idle Speed Motor Testing:

2. Plug the exerciser tool (7558) harness connector into the AIS motor.

3. Connect the red clip of exerciser tool (7558) to battery positive terminal. Connect the black clip to negative battery terminal. The red light on the exerciser tool will be illuminated when the exerciser is properly connected to battery.

4. Start engine.

^ When the switch is in the HIGH or LOW position, the light on the exerciser tool will flash. This indicates that voltage pulses are being sent to the AIS stepper motor.

5. Move the switch to the HIGH position. The engine speed should increase. Move the switch to the LOW position. The engine speed should decrease.

a. If the engine speed changes while using the exerciser tool, the AIS motor is functioning properly. Disconnect the exerciser tool and connect the AIS stepper motor wire connector to the stepper motor.

b. If the engine speed does not change, turn the ignition OFF and proceed to step (6). Do not disconnect exerciser from the AIS stepper motor.

6. Remove the AIS stepper motor from the throttle body.

CAUTION: When checking AIS motor operation with the motor removed from the throttle body, do not extend the pintle more than 6.35 mm (.250 in). If the pintle is extended more than this amount, it may separate from the AIS stepper motor. The AIS motor must be replaced if the pintle separates from the motor.

7. With the ignition OFF, cycle the exerciser tool switch between the HIGH and LOW positions. Observe the pintle. The pintle should move in-and-out of the motor.

a. If the pintle does not move, replace the AIS motor. Start the engine and test the replacement motor operation as described in step (5).

b. If the pintle operates properly, check the AIS motor bore in the throttle body bore for blockage and clean as necessary. Install the AIS motor and retest. If blockage is not found, refer to the appropriate Diagnostic Chart.