Idle Speed Motor Position Sensor: Testing and Inspection

Motor Position Sensor (MPS):

Idle Switch / Motor Position Sensor Locations:

To test the Motor Position Sensor, attached to the Idle Speed Control (ISC) servo (mounted on the throttle body), proceed as follows.

Motor Position Sensor Test Hook-up:

Motor Position Sensor Resistance Test:

1. Connect an ohmmeter between terminals 3 and 1 of the motor position sensor connector.
Terminal 3: Sensor power
Terminal 1: Sensor ground

2. Measure the resistance of the terminals.
Standard Value...4-7 Kohm

Motor Position Sensor Powered Test:

3. Attach an ohmmeter between terminals 1 and 2 of the motor position sensor connector.
Terminal 1: Sensor ground
Terminal 2: MPS output


4. Connect a 6V battery between terminals 1 and 2 of the ISC motor connector (to operate the ISC motor) and check to see that resistance of the MPS (step #3 hook-up) changes smoothly when the ISC motor is activated.
Standard Value...Approx. 0.5 Kohm increasing to 4-6 Kohm

5. If the standard value is not achieved, or if the change is not smooth, replace the ISC servo assembly.