Cruise Control: Description and Operation

Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions at vehicle speeds above 40 km/h (25 mph). Steep grades may cause variations in the selected vehicle speeds.

The following are the main components of the cruise control system:
^ The Powertrain Control Module (PCM)
^ The On/Off switch
^ The Resume/Accel Switch
^ The Set/Coast Switch
^ The TCC/Brake Switch
^ The stoplamp switch

Cruise Control Engaged
The cruise control system will engage and adjust vehicle speed based on the activation of the following cruise control switches:
^ On/Off
^ Resume/Accel.
^ Set/Coast

The cruise control switches are located on the multifunction/turn signal lever.

The PCM monitors the signal circuits of the cruise control switches in order to determine when to capture and maintain the selected vehicle speed.

Ignition positive voltage is supplied from the 10 ampere CRUISE fuse, to the cruise control switch. When the cruise control On/Off switch is in the On position, the PCM detects a high signal voltage on the cruise on switch signal circuit. When the Set/Coast button is pressed, the PCM detects a high signal voltage on the set/coast signal circuit. In order to engage the cruise control system, the On/Off switch must be On and the Set button momentarily pressed. The PCM will confirm that the cruise control enable criteria has been met. The PCM will also record the selected vehicle speed. When the Resume/Accel. switch is pressed, the PCM detects a high signal voltage on the resume/accel switch signal circuit. Pressing the Resume switch will recall the previous selected vehicle speed that is recorded in the PCM. Pressing the Accel. switch will allow the vehicle to accelerate to a vehicle speed greater than the current set vehicle speed. When the Accel. switch is released, the vehicle speed will decrease to the current set vehicle speed. Pressing the Coast switch will allow the vehicle speed to decrease from the current set without deactivating the cruise control system. When the Coast switch is released, the vehicle will accelerate to the current set vehicle speed.

Cruise Control Disengaged
The PCM disengages the cruise control operation based on the signals from the following switches:
^ The On/Off switch
^ The TCC/Brake Switch
^ The stoplamp switch

The TCC/Brake switch and the stoplamp switch are incorporated into an assembly and is used to disengage the cruise control. The stop lamp and TCC/Brake switch are mounted to the brake pedal bracket. Pressing the brake pedal while the cruise control is engaged will disengaged the cruise control system. When the brake pedal is pressed, the normally closed TCC/Brake switch opens and the normally open stoplamp switch closes. The PCM detects a low signal voltage on the TCC/Brake signal circuit and detects a high signal voltage on the stoplamp signal circuit. The vehicle speed stored in the memory of the PCM will be erased when the Off button is pressed, or the ignition switch is turned off.

Cruise Control Inhibited
The PCM inhibits the cruise control operation when any of the following conditions exist:
^ The vehicle speed is less than 40 km/h (25 mph).
^ The vehicle is in PARK, REVERSE, NEUTRAL, or 1st gear.
^ The engine RPM low.
^ The engine RPM is high, with fuel cut-off.
^ The vehicle speed is to high.
^ The battery is either overcharged or undercharged.
^ The antilock brake system/traction control system is active for more than 2 seconds.