Functional Description - Central ADAS Decision Module (CADM)
The CADM has several responsibilities in the AEB system. Some of those responsibilities are:
- The CADM is responsible for populating a CAN message indicating the status of the AEB system, the PEB system and the FCW system.
- The CADM receives and utilizes the AEB and PEB system state changes based on the customer preference selections in the DSM via an IPC bus message.
- The CADM receives and utilizes the steering wheel angle from the Electronic Power Steering (EPS).
- The CADM receives and utilizes the longitude, lateral, yaw, vehicle motion status, vehicle speed states and any brake system faults active signals from the BSM.
- The CADM receives and utilizes the gear engaged signal from the Transmission Control Module (TCM).
- The CADM receives and utilizes signals from the LRRF, MRRFL, MRRFR and the LRCF for collecting data and object information.
- The CADM receives and utilizes BCM signals to determines the ambient conditions from the wiper system and external temperature, the battery voltage.
- The CADM receives and utilizes a Powertrain Control Module (PCM) signal to determine the engine status and the accelerator pedal position status.
- The CADM receives and utilizes the odometer signal from the IPC to learn the vehicle odometer for the VIN learning process.
- The CADM receives and utilizes vehicle dynamics information from the ORC.
- The CADM monitors the message counter and the Cyclical Redundancy Check (CRC) for critical messages to ensure the integrity of the signals with that message. If an issue is detected in either the counter or the CRC, the CADM will request Malfunction Indicator Lamp (MIL) illumination and set the appropriate Diagnostic Trouble Code (DTC).
The CADM follows the strategy defined in the following table to set DTCs against external inputs to the CADM:
| Type of External Input Faulted or Providing Invalid Data | AEB Action |
|---|---|
| Vehicle dynamic data This includes yaw rate, longitudinal acceleration, steering angle input and wheel speed. |
AEB system is disabled. Indication is provided when the AEB is enabled and each time the AEB ON button is pressed. DTC is set as soon as a fault is detected |
| Brake sensor/ brake pedal position | AEB system is disabled. Indication is provided when the AEB is enabled and each time the AEB ON button is pressed. DTC is set when the AEB is enabled or the FCW ON button is pressed. |
| Engine - PCM | Faults in the engine will not prevent the AEB from requesting braking. |
| Transmission | Faults in the transmission have no effect on the AEB system. |
| IPC | AEB system is disabled. Indication is provided when the AEB is enabled and each time the AEB ON button is pressed. DTC is set when the AEB is enabled or the FCW ON button is pressed. |
| LRCF | AEB system is available with limited functionality. Braking on stationary objects is disabled. Indication is provided when the AEB is enabled and each time the AEB ON button is pressed. DTC is set when the AEB is enabled or the FCW ON button is pressed. |
| Electronic Park Brake (EPB) | Faults in the EPB system have no effect on the AEB system. |
| Cruise Control Switches | Faults in the cruise control switches have no effect on the AEB system. |
| Temperature sensor / indicator | AEB system is never disabled. No indication is provided. DTC is set when the AEB is enabled or the FCW ON button is pressed. |
| Door ajar switches | Faults in the ajar switches have no effect on the AEB system. |