Anti-Lock Brake System Operation (ABS)
The SLABS ECU is the Brains behind all of the vehicle Anti-Lock Braking operations. The SLABS ECU is a small rectangular black box that is located under the left hand seat. The ECU monitors various vehicle sensors and conditions and determines through a set of internal software controls, what is happening when you press the brake pedal. The SLABS ECU is constantly comparing the overall calculated vehicle speed to each individualy measured wheel speed. detects a variation in speed of both wheels on a single axle when the brakes are applied, it operates the inlet solenoids in the modulator unit relative to that axle. This has the effect of removing the brake pressure through the brake system on the axle with the slipping wheels.

Traction Control Operation (TC)
The SLABS ECU also manages all of the Traction Control Operations of the vehicle. In many ways, the TC functions are simply an extention of the existing ABS system. The same physical valves and sensor assemblies that can detect when your wheels are locked up, can also detect is your wheels are slipping too much. The primary difference between the TC and the ABS is the software pathway that is triggered inside the SLABS ECU. The Discovery 2 Vehicle does not employ a Viscous Coupling between the front and rear drive lines. Effectively the Discovery 2 vehicle has and open center, rear and front differential. This means that if any one of the four wheels looses traction, all of the engine power goes to the slipping wheel. This brings your forward progress to a complete halt. The vehicle relies solely on the TC system to modulate the open differentials and help control wheel slippage. The ABS ECU monitors each individual wheel speed sensors and the overall road speed. If one wheel on one axle or both wheels on one axle increase in speed compared to the other axle, the ABS pump will trigger. The ABS ECU then diverts hydraulic pressure to either one wheel or both wheels on the axle that has lost traction. The ABS system will operate up to 32 MPH. All ETC functions are suspended when the brake pedal is depressed. The TC can be active for an indefinite period of time.

Electronic Brake Distribution (EBC)
The EBC system is another extention of the ABS subsystem. Previous vehicle designs would limit the brake pressure to the rear of the vehicle through mechanical pressure regulators. It is important to regulate the amount of rear brake pressure during emergency braking situations. If the rear brakes are not limited, the rear of the vehicle could begin to overtake the front and cause a spin. The distribution of brake pressure is managed electronically. The ABS system electronically modulates the rear brake valves to limit the ammount of brake force applied.

Hill Descent Control (HDC)
The purpose of the HDC system is to provide control when descending steep gradients. The system applies the brakes automatically to assist the engine braking. The amount will depend upon the gear and the amount of throttle applied. The system give security in circumstances where the wrong gear has been selected. The ECU can accomplish this by distributing the braking pressure primarily to the downhill axle using the principles of the ABS system. Additionally, wheel slippage can be controlled by employing some of the ABS principles. The driver activates the system by selecting the low range on the transfer box and pressing the HDC switch. It is important that the brake pedal is not pressed as HDC mode will be canceled. HDC operates in all gears when in low range and can also function in neutral. There is no direct signal from the gearbox to the ABS ECU as to which gear has been selected. The ECU calculates this by using signals from the engine management system, engine speed signal and its own calculated road speed. If the ECU detects that no gear is selected or that the clutch is depressed then a fixed target speed is selected and the system will operate for 1 minute only. When the HDC system is in operation, the brake lights are illuminated by the ABS ECU regardless of the brake pedal position.