ACC Operation

The ACC system functions much like a standard cruise control system. The ACC system automatically adjusts the vehicle speed to maintain a set distance gap from the front of the vehicle and the vehicle in the same path of travel. When the ACC system is on and is following a vehicle or a vehicle enters the same driving lane, a follow vehicle graphic is displayed in the message center.

The ACC lane keeping system (if equipped), uses a forward looking camera mounted on the windshield to monitor vehicle movement within the travel lane. The lane keeping system alerts the driver by vibrating the steering wheel or aids the driver by providing a small steering input to move the vehicle back into the travel lane. Refer to the Owner's Literature for additional information.

The ACC system does not activate if the vehicle speed is below 20 kmh (12 mph) or if a lead vehicle is not detected. If either of these occur, the message center displays ADAPTIVE CRUISE - SPEED TOO LOW TO ACTIVATE.

Vehicles equipped with a 2.3L engine, the brake switch assembly (contains the stoplamp switch and cruise control deactivator switch) and APP sensor are direct inputs to the PCM.

Vehicles equipped with the 2.7L engine, the EBB (contains the stoplamp switch and cruise control deactivator switch). For additional information, Refer to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description .

The CCM is on a dedicated private CAN with the IPMA. The IPMA acts as a gateway and relays network messages and DTC information from the CCM to other modules that utilize the ACC system.

The CCM monitors the yaw rate signal from the ABS module and compares it to wheel speed and steering wheel angle signals. If the ABS module determines the yaw rate is invalid, the CCM disables the ACC. The message center displays the message COLLISION WARNING MALFUNCTION and/or ADAPTIVE CRUISE MALFUNCTION.

The CCM monitors the environment in front of the vehicle while active. If the radar beam is obstructed by a buildup of snow, ice, rain or other debris or the vehicle is driven in a desert environment with no other traffic for extended periods of time, the sensor triggers an ADAPTIVE CRUISE NOT AVAILABLE SENSOR BLOCKED SEE MANUAL message in the message center and disables the ACC. The ACC resumes once the obstruction is cleared and the radar is able to detect targets or upon a key cycle.

The ACC system does not engage properly if the CCM front radar sensor is not aligned correctly, the message center displays FRONT SENSOR NOT ALIGNED. The ACC resumes once the CCM is aligned and is able to properly detect targets.

The CCM vertical and horizontal alignment procedure is located in General Procedures. The horizontal alignment for the CCM is a calibration check performed by the scan tool to insure the CCM radar is pointed straight. The scan tool identifies this as, Alignment Offset with a horizontal specification of +/- 3.0 degrees offset. For additional information, Refer to: Cruise Control Radar Alignment .

The ABS module estimates brake temperature by monitoring applied brake pressure over a period of time and sends a message to the CCM when the estimated temperature is above a given threshold. An alarm sounds and the ACC system is deactivated until the estimated brake temperature returns to cooler operating conditions. This condition can happen in hilly or mountainous driving terrain.

ACC Indicator 

The ACC indicator located in the IPC illuminates a gray indicator lamp and displays the previous gap setting and SET graphic indicating the system is in standby mode. This notifies the driver the system is ready and the vehicle can accelerate to the desired speed. A green ACC indicator illuminates when the system is active. Refer to the Owner's Literature for additional information.

Gap Setting 

When a vehicle ahead enters the same lane or a slower vehicle is ahead in the same lane, the vehicle speed adjusts automatically to maintain a preset distance gap. Four horizontal bars with preset graph settings are displayed in the message center. Pressing up (decrease) or down (increase) on the steering wheel cruise control gap switch increases or decreases the distance from the vehicle ahead. If all of the bars are illuminated, this is the longest gap setting. If only one bar is illuminated, that is the shortest gap setting.

The vehicle maintains the distance gap to the vehicle ahead until:

• the vehicle ahead accelerates to a speed above the set speed.
• the vehicle ahead moves out of the lane or out of view.
• the vehicle speed falls below 20 kmh (12 mph).
• a new gap distance is set.

The distance gap is overridden by applying the accelerator pedal. The follow vehicle graphic is not displayed in the message center and the green indicator illuminates. When the accelerator pedal is released, the ACC system returns to normal operation and the vehicle speed decreases to the set speed or a lower if following a vehicle ahead.

The CCM commands the ABS module, which controls the brakes, to automatically apply the brakes to slow the vehicle to maintain a safe distance to the vehicle in front.

Steering Wheel Switch Function 

The ACC steering wheel mounted switches are momentary contact switches that toggle up and down for the cruise control switch state. Pressing and releasing the on (speedometer icon) switch turns the cruise control system on. Pressing SET+ and releasing the set switch sets the vehicle's speed and stores the set speed in memory. The ACC indicator illuminates and the message center displays the set speed and gap setting graphic.

There are two ways to change the set speed. The first way is to accelerate or brake to the desired speed and press and release the set cruise control switch until the desired set speed is shown on the message center. The second way is by tapping the SET+ or the SET- switch while in the set mode, increasing or decreasing the displayed set speed by 1.6 kmh (1 mph) per tap. If the respective button is pressed and held, the displayed set speed continues to increase or decrease until the button is released. The ACC system may apply the brakes to slow the vehicle down to the new set speed. The set speed displays continuously in the message center while the ACC system is active.

Pressing and releasing the off (speedometer icon) switch or switching the ignition to off, turns the ACC system off. The ACC set speed memory is erased.

Applying the brake pedal or pressing the CAN/RES switch puts the ACC system in standby mode and the last set speed is displayed in the message center with a strike-through. Pressing the RES switch when the ACC system is in standby mode causes the vehicle to accelerate to the last set speed. The set speed continuously displays in the message center while the ACC system is active. The resume (RES) switch does not function if the off switch is pressed, the ignition is cycled off or if the current vehicle speed is below the minimum operational speed.

The ACC system has the capability for the driver to change from ACC to standard cruise control. The steering wheel switches are used to switch from ACC to standard cruise control within the message center. For information on selecting the standard cruise control in the message center, refer to the Owner's Literature for additional information. Once the standard cruise control is selected in the message center, the ACC indicator is replaced by the standard cruise control indicator. The vehicle no longer responds to lead vehicles or automatic braking. Upon the next ignition cycle, the vehicle defaults back to the ACC system.

Pre-Collision Assist System Operation 

The pre-collision assist system is offered as a camera-only option without ACC. An additional safety feature on vehicles equipped with ACC uses both the CCM and the IPMA. The system is active whether the ACC system is on or off. If the system detects a vehicle, pedestrian or other object in the vehicle path of travel, the system provides three additional levels of functionality. For additional information,