Principles Of Operation

Cruise Control

Principles of Operation

The cruise control system is controlled by the PCM and the Instrument Panel Cluster (IPC). The cruise control system is designed to maintain a selected vehicle speed between 30 km/h (18 mph) and the maximum limited vehicle speed. The cruise control system is controlled by the steering wheel mounted switches (ON/OFF, SET+, SET-, and CAN/RES), brake pedal inputs and the clutch pedal cruise control deactivator switch (manual transaxle). The cruise control switches are hard-wired to the IPC (Instrument Panel Cluster). The IPC (Instrument Panel Cluster) sends a High Speed Controller Area Network (HS-CAN) network message to the PCM to control the cruise control system.

The clockspring provides the electrical interface between the steering column wiring and the cruise control switches in the steering wheel.

The cruise control functions include:

- turning on the cruise control system.

- setting and maintaining the desired vehicle speed.

- accelerating the vehicle speed.

- coasting down to a lower speed.

- resuming the prior vehicle speed.

- turning off the cruise control system.

Pressing and releasing the ON switch turns the cruise control system on. Pressing and releasing the SET+ or SET- switch while the vehicle is traveling at the desired speed activates the cruise control system. The cruise control indicator illuminates green to indicate the cruise control system is active.

Tapping the SET+ or the SET- switch while in the set mode, increases or decreases the maintained vehicle speed by 1.6 km/h (1 mph) per tap. If the respective switch is pressed and held, the vehicle speed continues to accelerate or decelerate until the switch is released.

Pressing and releasing the OFF switch, or turning the ignition switch to the OFF position, turns the cruise control system off. Applying the brake pedal or clutch pedal (manual transaxle) puts the cruise control system into standby mode.

The CAN/RES switch has a dual function for canceling or resuming the cruise control system. Pressing the CAN/RES switch, when the cruise control system is active moves the system into the standby mode (cancel function). The cruise control indicator turns off. Pressing the CAN/RES switch when the cruise control system is in the standby mode causes the vehicle to accelerate to the last set speed (resume function). The cruise control indicator illuminates to indicate the system is reactivated. Resume does not function if the OFF switch is pressed, the ignition switch is in the OFF position, or if the current vehicle speed is below the minimum operational speed.

The stoplamp switch and the cruise control deactivator switch are electrical inputs controlling the cruise control system. The stoplamp switch is a normally open switch that is hard-wired to the PCM. When the brake pedal is applied, the switch closes and applies a voltage signal to the PCM, deactivating the cruise control. The cruise control deactivator switch is a normally closed switch that is hard-wired to the IPC (Instrument Panel Cluster). When the brake pedal is applied, the switch opens and removes the ground signal from the IPC (Instrument Panel Cluster). The IPC (Instrument Panel Cluster) sends a HS-CAN (High Speed Controller Area Network) network message to the PCM to signal that the brake pedal is applied. The PCM compares the inputs from the stoplamp switch and the cruise control deactivator switch. If a deviation occurs, the PCM sets a DTC and the cruise control system is deactivated.

The clutch pedal cruise control deactivator switch is used on vehicles equipped with a manual transaxle. When the clutch pedal is pressed with the cruise control system engaged, the normally open switch closes and provides a ground signal to the IPC (Instrument Panel Cluster). The IPC (Instrument Panel Cluster) sends a HS-CAN (High Speed Controller Area Network) network message to the PCM to deactivate the cruise control system and place it in standby mode.

The inputs to the PCM are:

- Digital Transmission Range (TR) sensor (automatic transaxle)

- Cruise control switch(es) (networked from the IPC (Instrument Panel Cluster))

- Clutch pedal cruise control deactivator switch (manual transaxle) (networked from the IPC (Instrument Panel Cluster))

- Cruise control deactivator switch (networked from the IPC (Instrument Panel Cluster))

- Stoplamp switch (hard-wired)

The outputs of the PCM are:

- Electronic Throttle Body (ETB) command

- Cruise control Indicator (networked from the IPC (Instrument Panel Cluster))

The vehicle speed is controlled by the PCM through ETB (Electronic Throttle Body). Cruise control electronics are contained entirely within the PCM.

When the cruise control system is active, the PCM corrects for deviations in the actual vehicle speed by proportionally moving the throttle plate. The PCM modulates the throttle to minimize error between the actual vehicle speed and the desired speed.

The PCM strategy uses the throttle control for smooth accelerations.

The PCM sends a serial message over the HS-CAN (High Speed Controller Area Network) to the IPC (Instrument Panel Cluster) to command the cruise control indicator to be turned on or off.

In the event of an off command or a deactivation request from the cruise control deactivator switch, the cruise control system carries out a deactivation and immediately returns the throttle to the idle position.

The cruise control system provides self-diagnostics. The cruise control system disables operation and sets a PCM or IPC (Instrument Panel Cluster) DTC if it detects certain faults. The IPC (Instrument Panel Cluster) does not indicate cruise control faults with an indicator. Fault codes are logged by the PCM or IPC (Instrument Panel Cluster).

Additionally, the following conditions cause the cruise control system to deactivate:

- Transmission gear selector in a position other than D or OD (automatic transaxle)

- Clutch pedal is pressed (manual transaxle)

- The cruise control set speed is overridden with the accelerator pedal for a period longer than 5 minutes

- Vehicle speed loss from set speed of greater than 16 km/h (10 mph) occurs

- Vehicle speed falls below the minimum allowable limit of 30 km/h (18 mph)

- Cruise control switch pressed or stuck longer than 2 minutes

- ABS fault