Speed Control Systems: Notes

DESCRIPTION 

There are two available speed control systems on this vehicle:

• Normal Cruise Control (NCC)
• Adaptive Cruise Control (ACC) with Stop and Go
• Rough Road Cruise Control (RRCC) is implemented with both cruise systems available for 2023+ models.

Courtesy of CHRYSLER GROUP, LLC

1 - Long Range Radar Front (LRRF)

2 - Powertrain Control Module (PCM)

3 - Body Control Module (BCM)

4 - Long Range Camera Front (LRCF)

5 - Central ADAS Decision Module (CADM)

6 - Cruise Control Switch

7 - Instrument Panel Cluster (IPC)

8 - Brake System Control Module (BSCM)

ACC/NCC/RCC 

The CADM controlled ACC system is a convenience feature (not a safety system) that allows the driver to keep cruise control engaged while driving without having to constantly reset the system when approaching slower moving vehicles.

A moving vehicle is defined a vehicle that the system determines has a speed greater than zero (vehicle is in motion).

A stopped vehicle is defined as a vehicle that the system initially determined had a speed greater than zero, then came to a standstill (vehicle was in motion, then came to a stop/standstill).

A stationary vehicle is defined as a vehicle that the system has never determined to have a speed greater than zero (always at standstill).

The ACC system uses the sensor data fusion from RADAR and a LRCF to detect vehicle(s) in the forward path of the host vehicle that are moving, stopped and stationary.

If the ACC system detects a slower moving target vehicle in the path of the host vehicle, it will automatically decrease the speed of the host vehicle by sending torque, desired speed and gear requests to the PCM and TCM via the BSCM or a brake torque request directly to the BSCM.

The system decelerates the speed of the vehicle to the speed of the target vehicle, while maintaining a driver selected time-gap (distance) from the target vehicle. When the slower moving vehicle is no longer present, the system will accelerate the host vehicle back to the original set speed.

The ACC system is available above vehicle speeds of 0 mph.

The ACC system can also bring the vehicle to a standstill. The ACC system has an Electronic Park Brake (EPB), to keep the host vehicle at a stand-still for an period of time. After the vehicle is brought to a stand-still, the vehicle is initially kept at a standstill by the brake system, and after the brake system times out, EPB is activated and the ACC system is cancelled after two seconds. The ACC system activates the brake lamps.

When a vehicle is equipped with the ACC system, the NCC operation is also be controlled by the CADM. The driver can always use the NCC system if they prefer. The NCC is a conventional system with an addition of the CADM.

Overtake Aid - When the ACC is engaged and the vehicle is trailing a slower moving vehicle, the ACC system provides an overtake aid when the driver activates the turn signal indicator. The turn signal indicator activation is a status signal that the BCM receives and then sends to the CADM for processing. The overtake aid consists of additional amounts of acceleration while trailing the vehicle to aid in a lane shift maneuver. Overtake aid is only provided when the vehicle being to transition to the overtaking lane. The overtaking lane is on the left side in left hand drive counties and is on the right side in right hand drive countries. The CADM determines the flow of traffic by observing oncoming traffic and applying the side at which it provides overtake aid. The CADM inhibits the overtake aid if a target object is detected by the CADM in the lane the vehicle is transitioning to. The CADM also uses the MRRRR and the MRRRL to detect if a vehicle is present in the blind spot of the host vehicle. The CADM also inhibits overtake aid If a vehicle is detected in this region.

The following includes the ACC/NCC deactivation/cancellation conditions:

• The brakes are manually applied
• EPB is applied
• Driver door is ajar (ACC only)
• Driver seatbelt is unbuckled (ACC only)
• Vehicle is above or below a defined range of operation
• Vehicle is in 4LO
• Transmission is shifted to N  , R  , or P 
• Brakes are overheated
• Speed limiter function is active or is being activated
• Vehicle is on steep grade at low vehicle speed (ACC only)
• Forward Collision Warning (FCW) intervention
• Cancel button is pressed
• LRRF is misaligned (ACC only)
• Cancellation request from BSCM (BSCM event detected)
• BSCM internal failure or loss of communication exists
• Electronic Stability Control (ESC) failure
• CADM overheating condition
• CADM CAN error
• PCM or TCM is in limp home mode
• Fault in the brake pedal
• Fault in the cruise control switch module
• Fault in the accelerator pedal
• Faulted engine torque request by the PCM
• Engine stops
• Over rev detected
• Radar blocked (ACC only)
• EPB is faulted
• Steering wheel calibration is improper

RRCC is a 4-High feature intended to fill the gap between:

• Cruise control (minimum set speed 20 MPH).
• Selec-Speed Control (maximum set speed 5.6 MPH, restricted to 4WD Low).

The RRCC feature is turned On/Off with the Selec-Speed ICS control and vehicle speed is set using the cruise control SET button. The indicator will illuminate when activated.

There is a RRCC icon and Set Speed IPC indications displayed to the customer by the IPC which alert the customer of the following:

• Instruction Message: To inform the user on how to set the features speed.
• Information Messages: Feature set speed, when feature is canceled or unavailable.