Code B663 - Cruise Speed Difference: Notes

Code B663 will set and disengage the cruise control if the actual speed is 20 MPH higher or lower than the set speed. This code is used as a type of safety valve to the cruise control system, and can be set under normal conditions if the operator accelerates using the gas pedal and goes 20 MPH over the cruise set speed.

1. BCM data value BD70 displays commanded servo position. The commanded range is approximately 4 percent to 94 percent. If the servo will not go to full stroke, the vacuum supply, servo, or vacuum brake release circuit is leaking.
2. This step checks to see if the vacuum leak is due to brake release valve and circuit or servo and source vacuum.
3. This step checks to see if vacuum leak is due to vacuum source or servo.
4. This checks to see if fault is due to intermittent or slow vacuum leak.
5. This step checks to see if fault is servo or brake vacuum release circuit.