TESTING

1. Detach the ISC valve connector when the engine is cold and idling.
2. Note the engine rpm and reconnect the connector.
3. Warm the engine to normal operating temperature and detach the connector again.

   Fig. 1: To test the ISC valve, disconnect the IAC valve electrical plug

   Fig. 2: Measure the resistance across both terminals of the ISC valve, at the temperature specified in the text for each model

4. Verify the engine rpm is lower with the ISC detached when the engine is warm.
5. Check the resistance of the valve using an ohmmeter.
6. The resistance should be approximately:
   • 1990–92 626 and MX-6: 6.3–9.9 ohms at normal operating temperature.
   • 1993–98 626/MX-6/Probe: 7.7–9.3 ohms at 73°F (23°C).
   • 1990–94 323 and Protege: 11–13 ohms at 68°F (20°C).
   • 1995–98 Protege: 7.7–9.3 ohms at 73°F (23°C).
   • MX-3 and Millenia: 10.7–12.3 ohms at 68°F (20°C).
7. If not as specified, remove the valve from the throttle body.
8. Blow air through the valve port A and verify that no air comes out of port B when the valve is at normal operating temperature.

   Fig. 3: With the valve removed, cool it down at point A and watch the valve movement at B

9. Allow the valve to cool. Watch the movement of the valve as it cools, it should open.
10. Blow air through the valve port A and verify air comes out of port B when the valve is cold.
11. If not as specified, replace the valve.