Control Switch
- Push voltmeter positive lead into the Gray wire terminal at the emissions box connector. Connect negative probe to ground. Start the engine and check for voltage during deceleration. If voltage is present, test is complete.
- If voltage is not present, disconnect vacuum hose from emissions box and check for vacuum. If there is no vacuum, check vacuum line for leaks, blockage or disconnected hose and retest. If there is vacuum, check the vacuum line for leaks in emission box. If okay, replace control switch and retest.