Circuit Description

Cruise Control

How the Circuit Works
The vehicle does not use a throttle cable or cruise control actuator to maintain the vehicle speed during the cruise control mode. A throttle actuator control motor, located on the side of the throttle housing, is used to open and close the throttle plate for routine driving and cruise conditions.

Power Supply
Battery voltage is supplied at all times through fuse 1 (in the driver's under-dash fuse/relay box) to the switch contact of the DBW relay in the passenger's under-dash fuse/relay box. The coil side of the DBW relay is energized with battery voltage when the PGM-FI main 1 relay closes. The PCM grounds the coil of the DBW relay and the coil of the PGM-FI relay to close both relays. When the DBW relay closes, battery voltage is provided to the throttle actuator control module.

Fuse 7 (in the under-hood fuse/relay box) supplies battery voltage at all times to the relay control module. The relay control module is located in the under-hood fuse/relay box.

Fuse 13 (hot at all times) (in the under-hood fuse/relay box), and fuse 18 (hot in on or start) (in the driver's under-dash fuse relay box) supply battery voltage to the brake pedal position switch.

System Description
When the cruise main switch is pressed, a reference voltage at the gauge control module is grounded through G501 and the cruise main indicator illuminates. With the shift lever is in D, a path to ground is provided to the PCM, and the cruise control system can be set. When the set switch is pressed, a reference voltage signal is sent to the gauge control module and the cruise system is activated.

The gauge control module communicates the set signal via multiplex communication lines to the PCM. Using the vehicle speed input obtained from the output shaft (countershaft) speed sensor, the PCM communicates the cruise control information to the throttle actuator control module. The throttle actuator control module sends signals to and receives signals from the TP sensor/throttle actuator. The throttle plate opens and closes to maintain the set vehicle speed. When the brake pedal is pressed, a battery voltage input is sent to the PCM through fuse 13 (in the under-hood fuse/relay box) and the battery voltage input through fuse 18 (in the driver's under-dash fuse relay box) is removed from the PCM. The cruise control system is deactivated when the brake pedal is pressed. The PCM communicates the brake pedal pressed information via multiplex communication lines to the gauge control module.

When the resume switch is pressed, a reference voltage signal is sent to the gauge control module and the cruise control system is reactivated to the previously set speed. When the cancel switch is pressed, two reference voltage signals are sent to the gauge control module and the cruise system is deactivated. It is necessary to accelerate the vehicle to speeds above 25 mph to set the cruise control system.