P063

DTC PO63:

Cruise Control Circuit:

DESCRIPTION
Code P063 will set and disengage the cruise control if vehicle speed is 20 mph higher 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 higher than the cruise set speed.

TEST CONDITIONS
1. Cruise control enabled.
2. Cruise control engaged.
3. Cruise control servo position 39% or greater (PD70).

FAILURE CONDITIONS
Vehicle speed 20 mph higher than set speed for 0.5 second.

ACTION TAKEN
Powertrain Control Module (PCM) disengages cruise control.

NOTES ON FAULT TREE
1. PCM data value PD70 displays servo position. The range is approximately 4% to 94%. If the servo will not go to full stroke, the vacuum supply, servo, or vacuum brake release circuit is leaking.

2. Checking if brake vacuum release is functioning properly.

3. Checking if fault is with cruise servo or wiring. Frequency should cycle between zero and non-zero values.

NOTES ON INTERMITTENTS
This code will not be caused by vacuum leaks or vacuum supply problems. It can only be set by the vehicle exceeding the set speed by 20 mph.