Test SC-6A - Checking Cruise Control Operation

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For appropriate wiring diagram, see appropriate chassis wiring diagram in WIRING DIAGRAMS .

Reconnect and reassemble all previously tested components. Connect DRB to engine diagnostic connector so DRB display can be seen from driver's seat. Road test vehicle. Using DRB, read CUTOUT monitor on DRB display. If DRB display shows erratic vehicle speed, replace vehicle speed sensor. Perform TEST VER-4A .
If DRB does not display erratic vehicle speed, Place cruise control ON/OFF switch in ON position. With vehicle speed at a minimum of 35 MPH, press and release cruise control SET/DECEL switch. If DRB displays S/C ALLOWED and cruise control is inoperative, repair cruise control servo vacuum feed or mechanical problems as necessary. Perform TEST VER-4A . If DRB displays S/C ALLOWED and cruise control is operative, perform following:
- Check for cruise control disengagement without driver command by driving vehicle under various road conditions.
- If cruise control disengages without driver command, using DRB, read CUTOUT monitor S/C DENIED message. See appropriate DENIED MESSAGE in DRB INTERMITTENT FAULT MESSAGES and correct problem as necessary. Perform TEST VER-4A .
- If cruise control does not disengage without driver command, using DRB, read CUTOUT monitor. Compare GOAL value with SPEED value. If values are not within 2 MPH of each other, replace PCM. Perform TEST VER-4A . If values are within 2 MPH of each other, test is complete.
If DRB displays S/C DENIED, see appropriate DENIED MESSAGE in DRB INTERMITTENT FAULT MESSAGES and correct problem as necessary.

DRB INTERMITTENT FAULT MESSAGES

Denied Message	Problem To Correct
BRAKE	Open Circuit At PCM Terminal No. 29
ON/OFF	No ON Signal From Switch At PCM Terminal No. 493
P/N	Grounded Circuit At PCM Terminal No. 30
RPM/SPD	PCM Senses High RPM For Given Vehicle Speed
SPEED	Speed Read At PCM Terminal 47 Lower Than 36 MPH
RPM	Engine RPM Is Excessively High
SOL/FLT	Fault In Servo Vent Or Vacuum Solenoid Circuit That Is Either Maturing Or Set

NOTE: Cruise control on-board diagnostic tests skip from TEST SC-6A to TEST TC-7A. No test procedures have been omitted.