Closed Throttle (Idle) Switch

All testing should be performed with ISA plunger in fully extended position, as it should be when engine is Off. If it is necessary to manually extend plunger, the ISA is probably defective.
1. With ignition switch On, connect voltmeter between terminals D2-13 and D2-7 of diagnostic connector. Observe voltmeter.
2. Voltmeter reading should be close to zero at closed throttle, and above 2 volts when off closed throttle position.
3. If voltage reading is zero in all positions, check for short to ground in wire harness or switch, or for open circuit between ECU connector terminal 25 and switch.
4. If voltage reading is greater than 2 volts in all positions, check for open circuit between ECU and switch connector, or between switch connector and ground.
5. Repair or replace wiring as necessary.