3F Speed Control Servo Operation

1. Connect the speed control servo connector and the diagnostic read-out tool.
2. Disconnect the speed control servo vacuum supply hose from the power brake booster and connect an auxiliary vacuum supply to it.
3. Place the system in the ATM Test 08.
4. Continuously apply 5 to 15 inches of vacuum to servo.
NOTE: Too little vacuum will not move the servo, too much may cause it to lock up.
5. If the system turns on and off while vacuum is being applied, and the throttle is opening and closing, check vacuum supply to the speed control servo. Check speed sensor operation using Engine Running Test 71. With a warm engine, miles per hour shown on readout box must be stable at all times. If not, replace the speed sensor.
6. If the system turns on and off while vacuum is being applied and the throttle is not opening and closing, replace the speed control servo.
NOTE: Before replacing the servo, make sure the speed control cable is properly adjusted and is not broken or make sure there are no leaks or restrictions in the vacuum supply hose.