Adaptive Speed Control Module
The Adaptive Speed Control Module (ASCM) is mounted on a bracket which is attached to the front armature.
The ASCM contains a forward looking radar transceiver together with related controlling hardware and software. A High Speed (HS) Controller Area Network (CAN) chassis bus connection allows the ASCM to communicate with other system control modules. Power supplies to the ASCM are from the extended ignition relay in the Rear Junction Box (RJB).
The ASCM is active whenever the ignition is on, even if speed control is not engaged. This is necessary in order to operate the forward alert, Advanced Emergency Brake Assist (AEBA) and Intelligent Emergency Braking (IEB) functions. With the ignition on, the ASCM is electrically powered, but no radar transmissions are emitted until the vehicle starts moving.
The ASCM transmits a radar beam forward of the vehicle and detects the returning signals reflected off other vehicles and objects ahead. The radar beam is electronically scanned in 7 zones across a total arc of 30° centered on the longitudinal axis of the vehicle. The vertical coverage of ±5° from nominal position. The radar operates at millimetric wavelengths (76 - 77 GHz) and transmits a frequency modulated continuous wave signal at a relatively low power level (no high power pulses). The ASCM detects the range, relative velocity and angle of objects within the scanned arc for up to a distance of approximately 150 meters (500 feet).
The ASCM compares vehicle speed data from the Anti-lock Brake System (ABS) control module with the relative speed of an external object. The speed of the objects is detected by the radar to determine that the object is stationary or not. If tires are different in diameter from those specified for the vehicle, the speed of the vehicle will not be the true road speed. The speed of the vehicle is calculated by the ABS control module. This situation may cause stationary objects to be falsely identified as moving vehicles and result in automatic deceleration on a clear road.
The ASCM continuously monitors both moving vehicles and stationary objects to determine if ASCM can 'see' normally.
The ASCM is physically blocked, if one of the following occurs:
- There are few roadside objects in the area.
- Other vehicles in the area.
- Accumulation of snow or mud on the lower grille of the front bumper.
- Incorrectly mounted license plate.
The ASCM then inhibits adaptive speed control and records a Diagnostic Trouble Code (DTC). The system will reset after an ignition cycle. In this case the ASCM does not have a fault and should not be replaced.
The ASCM must be mechanically vertically leveled if replaced in service. Horizontal alignment is achieved by putting the ASCM into service mode using the Jaguar Land Rover approved diagnostic equipment. The vehicle then needs to be driven for a short period while the ASCM performs a calibration routine. Calibration is complete when the follow mode warning indicator in the Instrument Cluster (IC) stops flashing.