Adaptive Speed Control
SPEED CONTROL SWITCHES
| ITEM | DESCRIPTION |
|---|---|
| 1 | Set + (engage/accelerate) switch |
| 2 | RES (resume) switch |
| 3 | Time gap decrease switch |
| 4 | - (decelerate) switch |
| 5 | CANCEL switch |
| 6 | Time gap increase switch |
The adaptive speed control switches are the same as used for standard speed control, with the addition of two time gap switches. The time gap switches allow the driver to adjust the follow mode and forward alert functions to one of four pre-set time gaps (gap 1 = 1 second; gap 2 = 1.4 seconds; gap 3 = 1.8 seconds; gap 4 = 2.2 seconds). The selected time gap is displayed in the message center when the time gap switches are operated.
When adaptive speed control is engaged, the time gap switches adjust the follow mode time gap. When adaptive speed control is disengaged, the time gap switches adjust the forward alert time gap (provided forward alert is enabled in the instrument cluster menu). The follow mode function defaults to the gap 3 setting each time the ignition is switched on. The forward alert function recalls the last selected time gap when the ignition is switched on.
ADAPTIVE SPEED CONTROL MODULE
| ITEM | DESCRIPTION |
|---|---|
| 1 | Adaptive speed control module |
| 2 | Mounting bracket |
| 3 | Adjuster screw |
The adaptive speed control module is attached to a bracket located in the armature of the front bumper, to the right of the vehicle centerline. A foam block in the bumper armature eliminates radar signal reflections within the armature.
The adaptive speed control module contains a forward looking radar transceiver together with related controlling hardware and software. A high speed CAN bus connection allows the adaptive speed control module to communicate with other system control modules. Power supplies to the adaptive speed control module are from the extended ignition relay in the RJB (rear junction box) and the ignition relay in the EJB (engine junction box).
The adaptive speed control module is active whenever the ignition is on, even if speed control is not engaged, in order to operate the forward alert, advanced emergency brake assist and intelligent emergency braking functions. With the ignition on, the adaptive speed control module is powered up but no radar transmissions are emitted until the vehicle is in motion.
The adaptive speed control module 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 at a rate of 20 sweeps/second across a total arc of 20° centered on the longitudinal axis of the vehicle. 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 control module detects the range, relative velocity and angle of objects within the scanned arc for up to a distance of approximately 130 meters (426.5 feet).
The adaptive speed control module compares vehicle speed data from the ABS control module with the relative speed of an external object as detected by the radar to ascertain whether the object is stationary or not. If tires are fitted which are different in diameter from those specified for the vehicle, the vehicle speed, calculated by the ABS module, will not be the true road speed. This situation may cause stationary objects to be falsely identified as moving vehicles and result in automatic deceleration on a clear road.
The adaptive speed control module continuously monitors both moving vehicles and stationary objects to determine if it can 'see' normally. If the control module can detect only a few objects, because it is physically blocked (for example by an accumulation of snow or mud on the lower grill of the front bumper, or an incorrectly located number plate), it is incorrectly aligned, or there are few roadside objects or other vehicles in the area, it may determine that it is blocked. The control module then inhibits adaptive speed control and records a DTC (diagnostic trouble code). The system will reset once the cause of the blockage is removed. In this case the control module is not faulty and should not be replaced.
If the adaptive speed control module is replaced in service it must be mechanically aligned vertically using the adjuster screw. Horizontal alignment is achieved by putting the control module into service mode using approved Land Rover diagnostic equipment. The vehicle then needs to be driven for a short period while the control module calibrates itself. For additional information, refer to: