Frequency Valve: Testing and Inspection

1. Remove fuel pump relay from the fuse panel and connect a jumper wire across sockets 13 and 14 to energize the fuel pump circuit.
2. If equipped, disconnect air flow sensor plate position indicator plug at air flow sensor.
3. Turn ignition on.
4. The frequency valve should operate, making a buzzing noise.
5. If no buzzing is heard, check the wiring.
a. Disconnect the plug on the frequency valve.
b. Connect a voltmeter across the terminals. Battery voltage should be available while fuel pump is energized.
c. If no voltage is present, check ground circuit, power circuit, and check wiring for breaks.
6. If voltage is present, and wiring is OK, replace frequency valve.