P063

DTC P063:

Cruise Control Circuit:

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 CONDITION
Vehicle speed 20 mph higher than set speed for 0.5 second.

ACTION TAKEN
PCM disables cruise control.

NOTES ON FAULT TREE
1. If Code P075 (vehicle speed sensor signal interrupt) is set, diagnose it first because it can cause other speed related problems.
2. Checking to see if the cruise control feedback is a value that it should never be even with cruise control servo fully released (0 to 6).
3. Checking if the Powertrain Control Module (PCM) and circuitry to the cruise control servo is OK (measure 4.6 to 5.1 volts).
4. Checking CKT 398 for a short to voltage.
5. Checking if cruise control servo is able to respond correctly to the signal from the PCM.

NOTES ON INTERMITTENTS
If Code P063 is setting intermittently, make sure owner is not overrunning set speed by more than 20 mph. 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.