Flow Chart No. 3: Set Speed Fluctuates

Flow Chart No 3 - Symptom - Set speed fluctuates.

Step 1
Check that condition occurs only while using cruise control.
1. Verify that engine is properly tuned.
2. Verify that condition does not occur when driving without cruise control.




3. Does condition occur without cruise control?

Step 2
Check for binding in cruise control actuator cable and throttle body linkage.
1. Check for binding or sticking of cruise control cable or throttle linkage and throttle plate.
2. Make sure throttle cable bracket and cruise control servo bracket are not loose.




3. Are components OK?

Step 3
Check vehicle speed sensor (VSS) circuit.




1. Measure resistance between Pin 3 (GY/B) and Pin 10 (P/O).




2. Is resistance between 190 and 250 ohms?

Step 4
Check VSS.
1. Remove VSS connector.




2. Measure resistance across VSS terminals.




3. Is resistance between 190 and 250 ohms?

Step 5
Road test vehicle.
1. Road test vehicle and observe speedometer needle.




2. Does the needle waver?

Step 6
Check cruise control servo assembly.
1. Substitute known good cruise control servo.
2. Test vehicle for proper operation.




3. Does system operate properly?