Idle Speed Motor Position Sensor: Testing and Inspection

CAUTION: When the selector lever is shifted to the D range, the brakes should be applied and the vehicle should be prevented from moving forward.

CIRCUIT DIAGRAM





INSPECTION USING SCAN TOOL











HARNESS INSPECTION PROCEDURE

COMPONENT TEST PROCEDURE
1. Disconnect the idle speed control motor position sensor connector.





2. Measure the resistance between terminals 2 and 3.

Standard value: 4 - 6 K Ohms

3. Disconnect the idle-speed control motor connector.





4. Connect 6 Volts DC between terminals 1 and 2 of the idle speed control motor connector, and then measure the resistance between terminals 3 and 5 of the idle speed control motor position sensor connector when the idle speed control motor is activated (caused to expand and contract)

Standard value: It should decrease smoothly as the idle speed control motor plunger contracts.

CAUTION: Apply only a 6 Volts DC or lower voltage. Application of higher voltage could cause locking of the servo gears.

5. If there is a deviation from the standard value, or if the change is not smooth, replace the idle speed control motor assembly.

TROUBLESHOOTING HINTS
- The idle speed control motor position sensor is the most important sensor used in controling the idle speed. In many cases where failures occur due to changes in the engine load, as when the air conditioning switch is turned on while the engine is idling, the fault lies with this sensor.
- If the output voltage of the idle speed control motor position sensor deviates from the standard value even though the results of checks of the idle speed control motor position sensor wire harness and individual components are normal, the following problems may have occurred.
- The basic idle speed adjustment is faulty.
- There are deposits on the throttle valve.
- Air is being sucked into the intake manifold through gaps in the gasket, etc.
- The EGR valve seat is sealed poorly.
- Combustion in the cylinder is poor. (The spark plugs, ignition coil, injectors, compression pressure, etc. are faulty.)