Description And Operation - Conventional
DESCRIPTION
The Cruise Control system if comprised of the following components:
| 1. | Refer to POWERTRAIN CONTROL MODULE (PCM) . |
| 2. | Refer to ANTILOCK BRAKE SYSTEM (ABS) MODULE . |
| 3. | Refer to BODY CONTROL MODULE (BCM) . |
| 4. | Refer to INSTRUMENT PANEL CLUSTER (IPC) . |
| 5. | Refer to STEERING WHEEL SWITCH (SWS) . |
OPERATION
- The driver of the vehicle presses any of the cruise control specific buttons.
- The cruise control switch transits the request over the Local Interface Network (LIN) bus to the BCM.
- The BCM transmits this information over the Controller Area Network - Chassis (CAN-C) bus to the PCM.
- The PCM manages the algorithm in order to keep the vehicle speed set by the driver.
The cruise control automatically disables when:
- Pressing the brake pedal
- Pressing the clutch pedal
- Turning OFF the ignition
A activated system is indicated by a light on the instrument panel, connected via the CAN network to the engine management.
| Refer to COMPONENT INDEX . |
The ABS module provides bus messages to the PCM, then provides the appropriate electronic message and hard wired outputs to invoke the requested cruise control features.
| Refer to COMPONENT INDEX . |
The BCM receives cruise control input requests from the steering wheel switch pod over the LIN bus.
The BCM converts the LIN messages to CAN-C and sends the message to the PCM.
| Refer to COMPONENT INDEX . |
Displays the cruise control indicator when activated. This request is sent by the PCM to the IPC.
| Refer to COMPONENT INDEX . |
The cruise control function is managed by the PCM.
The PCM software continually monitors cruise control inputs as well as electronic vehicle distance message inputs from the ABS module and numerous hardwired inputs including the brake (or stop) lamp switch, then provides the appropriate electronic message and hard wired outputs to invoke the requested electronic cruise control features.
If the PCM detects a fault on one of the following systems, it will disable the cruise control system. The PCM will store an appropriate Diagnostic Trouble Code (DTC).
- Vehicle Speed Sensor
- Sensor or actuators of the electric throttle (only for gasoline engines)
- Accelerator Pedal Position Sensor (APPS)
- Brake Pedal Position
- Clutch Switch rationality
- Engine Load sensor (only for gasoline engines)
- Ignition Coils (only for gasoline engines)
- Fuel Injectors
- High pressure system components (only for GDI and Diesel engines)
- Turbo sensors or actuators.
The PCM monitors all of the cruise control system electrical circuits to determine the system readiness. If the PCM detects a monitored system fault, it sets and stores a DTC. The PCM uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the CAN data bus.
Speed Limiter Function
The Speed Limiter function allows limiting the speed of the vehicle to customer programmable values. The speed limiter button is located on the steering wheel below the speed control buttons. The maximum programmable speed is 30 km/h (19 mph).
| Refer to COMPONENT INDEX . |
The cruise control switch pod receives battery power from a fuse located in the BCM
The vehicle operator controls all conventional cruise control system features through the cruise control switch pod on the face of the right horizontal spoke of the steering wheel. When a push button of the switch pod is pressed, it provides a bussed LIN input to the BCM.
The cruise control button functions:
- ON/OFF - It is an momentary button used to activate and deactivate the system. If the Speed Limiter is turned ON, the first pulse will turn OFF the Speed Limiter, the second pulse will turn ON the Cruise Control.
- SET/-
- It is an momentary button used to command three different functions (described below) according to the pushing activation mode and cruise control state: set, decelerate and tip-down.
- Set
- When cruise control is not regulating the vehicle speed, but is able to receive commands and the vehicle current speed is valid, a pulse or continuous activation of this button, causes the following actions:
- the vehicle speed at button release, is stored at the instant value of activation;
- the cruise control at button release, becomes active, that is the vehicle speed is under regulation.
- Decelerate - When C.C. is already "Active", a continuous activation of the button (that is: activation of the button exceeds a calibrated threshold value t_Thresh) will decrease the speed set target with pre-arranged, adjustable gradient (Delta_cont) till the minimum value allowed. When the button is released, the system stores the new speed reached by the vehicle.
- Tip Down - When C.C. is already "Active", a pulse activation of the button (that is: activation of the button does not exceed a calibrated threshold value t_Thresh) will decrease the speed set point of a constant adjustable step (Delta_pulse) till the minimum value allowed. When the button is released, the system stores the new speed value.
This function will not be activated if the current vehicle speed is not valid (button pressure will not have any effect).
- Set