Speed Control Solenoid Circuits (Non-OBD II)

Name of code:
Speed Control Solenoid Circuits

When Monitored:
Engine running, speed control switch on and battery voltage greater than 10.4 volts.

Set Condition:
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 35-85 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 solenoid to open the throttle and actuates the vent solenoid to close the throttle. These actuations are dependent on power vent solenoid to close the throttle. These actuations are dependent on power supplied to the servo from the PCM through the brake switch. The system is deactivated by pressing the brake, turning the on/off switch off, transmission going into neutral or high rpm. Reactivation can be done by repeating the previous steps or pressing resume with the vehicle speed between 35-85 mph.

Possible Causes:
- Solenoid control circuit open or shorted
- Vacuum or vent solenoid shorted or open
- Open or shorted speed control power supply circuit
- PCM failure