Code P063, Vehicle Speed & Set Speed Difference: Action

WARNING: This page is about a different car, the 1995 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.

PCM disengages cruise control.

NOTE: Test numbers refer to numbers on diagnostic chart.

PCM data value PD70 displays servo position. Range position is about 4-94 percent. If servo will no go full stroke, the vacuum supply, servo or vacuum brake release circuit is leaking.
Checks if brake vacuum release is functioning properly.
Checks if fault is with cruise servo or wiring. Frequency should cycle between zero and a non-zero values.