Servo Valve

Servo Valve Check:

1. Measure resistance between terminals. It should be 25 - 30 ohms.
2. With valve installed on vehicle, use the following steps to check that vacuum output is correct:

CAUTION: Disconnect servo valve from system before applying current. To prevent a sudden increase in engine speed, disconnect solenoid valve side vacuum hose.

a. Disconnect solenoid valve side vacuum hose at servo valve and connect vacuum gauge.
b. Warm engine to operating temperature.
c. Apply 0.3A current between terminals. Use a variable resistor rated at about 20 ohms / 5W to adjust current flow.
d. With current adjusted, vacuum should read 2.17 - 3.35 inHg (55 - 85 mmHg).
e. If not as specified and not other problems are detected (defective vacuum hose, etc.), replace valve.