Speed Control Solenoid Circuits

NAME OF CODE:
Speed Control Power Relay Circuit

WHEN MONITORED:
With the ignition key ON, speed control switched ON and the SET button pressed.

SET CONDITION:
When the powertrain control module actuates the vacuum and vent solenoids but they do not respond.

THEORY OF OPERATION:
When the "SET" switch is pressed the vehicle must be moving forward at a speed between 35 and 85 mph, with the transmission gear selector in other than park or neutral. The PCM locks in a set speed. Then the PCM energizes the vacuum and vent solenoid to open the throttle and deactivates the vent solenoid to close the throttle. These actuations are dependent on power supplied to the servo from either the speed control relay or the PCM. The system is deactivated by pressing the brake, turning the on/off switch to OFF, or vehicle speed falling below the minimum. Reactivation can be done by repeating the previous steps or pressing resume with the vehicle speed between 35 and 85 mph.

POSSIBLE CAUSES:
- Solenoid control circuit open or shorted
- Vacuum or vent solenoid shorted or open
- PCM failure