DSC switch
The DSC switch allows you to disable the DSC function. While Land Rover recommends enabling DSC for all normal driving conditions, disabling DSC may be beneficial in the following conditions to improve traction:
- Car needed "swing", to release from loose or soft ground.
- When driving on loose surfaces or with snow chains.
- When driving in deep sand, snow or mud.
- When driving on a deep longitudinal track.
The DSC switch is not latched. It is installed on the center switch panel of the instrument panel. Pressing the DSC switch supplies ignition voltage to the ABS module (anti-lock braking system). When the DSC switch is pressed for the first time, the ABS module (anti-lock braking system) turns off the DSC functions. When the DSC switch is pressed again, the ABS module (anti-lock braking system) re-enables DSC functions. In order for the ABS module (anti-lock braking system) responded to pressing the DSC switch, the switch must be held down for at least 0.3 s. The DSC function is activated automatically at the beginning of each ignition cycle.
The status of the DSC switch is indicated by the DSC indicator lamp. The DSC indicator lamp does not light up when the DSC function is on and stays on when the DSC function is off.
A request from the DSC switch to disable DSC is ignored if the air suspension system is faulty, or if the suspension height is set to off-road at speeds over 60 km/h.
To protect against mismanagement or switch failure, the ABS module (anti-lock braking system) stores a fault code if the signal from the DSC switch is high for more than one minute.
Even when the DSC function is disabled, vehicle maneuvers with excessive yaw or lateral acceleration may cause the function to be activated to stabilize the vehicle.
HDC switch
The HDC switch controls the activation of the HDC function.
The HDC switch is non-latching and is mounted on the center console behind the gear lever. Pressing and releasing the HDC switch briefly applies ignition voltage to the ABS module (anti-lock braking system). The first time you press and release the HDC switch, the ABS module (anti-lock braking system) Enables the HDC function. When the switch is subsequently pressed and released, the ABS module (anti-lock braking system) disables the HDC function.
To protect against incorrect operation or malfunction of the switch, the function status does not change if the switch is held down for more than 10 seconds. If the HDC switch input is high for more than one minute, the ABS module (anti-lock braking system) the fault persists.
HDC relay
The HDC relay is used to turn on the brake lights when the brakes are applied by the HDC function and also when the parking brake is applied dynamically.
The HDC relay is a maintenance-free solid state relay mounted on a CJB printed circuit board (switching unit). The HDC relay is controlled by the ABS module (anti-lock braking system), closing its winding to ground. ABS module (anti-lock braking system) monitors the hydraulic pressure of the brake system and activates the HDC relay when braking is active. A pressure threshold and a time filter are used to prevent the brake lights from flashing when braking.
Stoplight switch
The brake light switch is mounted on the brake pedal bracket and is actuated by the brake pedal. The brake light switch is a two-pole switch: brake switch pole (BS) sends a brake pedal status signal to the ABS module (anti-lock braking system); brake light switch pole (BLS) turns on the brake lights and also sends a brake pedal status signal to the ABS module (anti-lock braking system) and in ECM (engine control module).
When releasing the brake pedal:
- BS contacts close and provide ignition voltage from CJB (switching unit) to the ABS module (anti-lock braking system).
- BLS contacts are open.
When pressing the brake pedal:
- BS contacts are open.
- The BLS contacts close and provide ignition voltage from the CJB (switching unit) for three brake lights, to the ABS module (anti-lock braking system) and in ECM (engine control module m).
ABS module (anti-lock braking system) monitors the status of the signals from the brake light switch and transmits the brake pedal status and the corresponding quality factor via the CAN bus (local area network of controllers).
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