Cruise Control Module
| ITEM | DESCRIPTION |
|---|---|
| 1 | Mounting bracket |
| 2 | CCM |
| 3 | CCM bracket |
| 4 | Electrical connector |
The CCM is located behind the front lower grille on the right of the vehicle.
The CCM contains a forward looking radar transceiver together with related controlling hardware and software. A HS CAN chassis systems bus connection allows the CCM to communicate with other system control modules. Power supplies to the CCM are from the extended ignition relay in the Passenger Junction Box (PJB).
The CCM is active whenever the ignition is ON, even when cruise control is not engaged. The 'Forward Alert', Advanced Emergency Brake Assist (AEBA) and the emergency braking functions also use the CCM. With the ignition ON, the CCM is electrically powered, but no radar transmissions are emitted until Power Mode 7 (engine running).
The CCM 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 across a total arc of 30° centered on the longitudinal axis of the vehicle. The vertical coverage is ±5° from the nominal position of -2° (pointing down), which gives the best detection performance. The radar operates at millimetric wavelengths (76 - 77 GHz) and transmits a frequency modulated continuous wave signal at a relatively low power level. The CCM detects the following of objects within the scanned arc for up to a maximum distance of 140 m (500 feet):
- The range
- The relative velocity
- The angle.
The CCM compares vehicle speed data from the ABS 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. When tires are equipped which are different in diameter from those specified for the vehicle it may cause an incorrect road speed to be calculated. The incorrect information may cause stationary objects to be falsely identified as moving vehicles. The detection of falsely moving vehicles may result in the speed of the sensing vehicle decreasing.
The CCM continuously monitors both moving vehicles and stationary objects to determine when it can 'see' normally. There are situations when the CCM may determine that it is blocked:
- When physically covered or obstructed, for example, by an accumulation of snow or mud on the radiator grille.
- When the CCM can detect only a few objects.
- When unusual environments such as tunnels and roadworks cause distortion of the radar beam.
The CCM then inhibits adaptive cruise control and records a Diagnostic Trouble Code(s) (DTC). The adaptive cruise control system resets within same ignition cycle. In this case the CCM does not have a fault and should not be replaced.
The CCM does not require mechanical alignment when it is replaced in service. Horizontal and vertical alignment is achieved by putting the CCM into service mode using the Jaguar Land Rover (JLR) approved diagnostic equipment. The vehicle then needs to be driven for a short period when the CCM does a calibration routine. Calibration is complete when the 'Follow Mode' warning indicator in the IPC stops flashing.
The service alignment process measures the path of stationary targets. For example, streetlights, railings, road signs and parked vehicles. The service alignment process uses this data to correct for radar misalignment.
Alignment completes more quickly when more suitable targets are seen.
The following recommendations help:
- The speed must be above 40 km/h (25 mph).
- Try to keep the speed constant. The process takes longer to complete when the speed is not constant.
- Choose a road with plenty of stationary objects. For example, lamp posts, railings, street signs or parked vehicles. Use an inside or outside lane.
- Following vehicles too closely obscures the stationary targets from the radar, a time gap of at least 2 seconds is recommended.