Land Rover Anti Lock Control Traction Control Rover Manual

Schematic of HCU
Master cylinder1
Reservoir2
Brake booster3
Brake pedal4
HCU5
Pressure sensor6
Priming valve7
Pilot valve8
Return pump motor9
Return pump10
Inlet valve11
Relief valve12
Accumulator13
Outlet valve14
Anti-Lock Control - Traction ControlLesson 2 – Chassis
145Technical Training (G421079) 

Left front brake15
Right front brake16
Right rear brake17
Left rear brake18
The HCU has three operating modes: Normal
braking/EBD, ABS braking and active braking.
Normal Braking/EBD Mode
Initially, all of the solenoid operated valves are
de-energized. Operating the brake pedal produces a
corresponding increase or decrease of pressure in the
brakes, through the open pilot valves and inlet valves.
If the ABS module determines that EBD is necessary,
it energizes the inlet valves for the brakes of the...

ABS Module Harness Connector C0506 Pin Details
Input/OutputDescriptionPin No.
OutputGround1
InputBattery power supply2
InputBattery power supply3
OutputGround4
InputFront left wheel speed sensor signal5
OutputRear left wheel speed sensor power supply6
OutputRear right wheel speed sensor power supply7
InputRear right wheel speed sensor signal8
OutputFront right wheel speed sensor power supply9
InputFront right wheel speed sensor signal10
-Not used11 and 13
Input/OutputHigh speed CAN bus low14
InputYaw...

Input/OutputDescriptionPin No.
-Not used32
OutputRoad speed signal33
-Not used34
Input/OutputHigh speed CAN bus high35
InputHDC switch36
OutputYaw rate and lateral acceleration sensor test37
-Not used38 to 40
InputStoplamp switch BS contacts41
-Not used42 to 46
SYSTEM OPERATION
ABS
ABS controls the speed of all road wheels to ensure
optimum wheel slip when braking at the adhesion limit.
This prevents the wheels from locking, which helps to
retain effective steering control of the vehicle.
On the front...

acceleration sensor. The tracking stability is compared
with stored target data and, whenever the tracking
stability deviates from the target data, the ABS module
intervenes by applying the appropriate brakes. On
vehicles with an automatic transmission, when the DSC
function is active, the ABS module also signals the
Transmission Control Module (TCM) to prevent gear
shifts. If necessary, the ABS module also signals:
•The ECM, to reduce engine torque.
•The transfer box control module, to adjust the...

EDC
EDC prevents wheel slip caused by any of the following:
•A sudden decrease in engine torque when the
accelerator is suddenly released.
•The sudden engagement of the clutch after a
downshift on manual transmission vehicles.
•A downshift using the CommandShift™ on
automatic transmission vehicles.
When the ABS module detects the onset of wheel slip
without the brakes being applied it signals the ECM, on
the high speed CAN bus, to request a momentary
increase in engine torque.
HDC
HDC uses brake...

Low Range Target Speeds
Speed, km/h (mph)Limit
Gear
Manual TransmissionAutomatic Transmission
2 to 61, RD, 2 to 61, R
6 (3.75)3.5 (2.19)6 (3.75)3.5 (2.19)Default
3.5 (2.19)3.5 (2.19)3.5 (2.19)3.5 (2.19)Minimum
20 (12.5)20 (12.5)20 (12.5)20 (12.5)Maximum
High Range Target Speeds
Speed, km/h (mph)Limit
Gear
Manual TransmissionAutomatic Transmission
1, RD1, R
6 (3.75)10 (6.25)6 (3.75)Default
6 (3.75)6 (3.75)6 (3.75)Minimum
20 (12.5)20 (12.5)20 (12.5)Maximum
The target speed is varied between the minimum...

neutral, or because of brake overheat, the HDC function
remains in standby and resumes operation when the
accelerator pedal is released or the brakes have cooled.
The fade out strategy increases the target speed, at a
constant acceleration rate of 0.5 m/s2 (1.65 ft/s2), until
the maximum target speed is reached or until no active
braking is required for 0.5 s. If the accelerator pedal is
positioned within the range that influences target speed,
the acceleration rate is increased to 1.0 m/s2 (3.3 ft/s2)....

ANTI-LOCK CONTROL DIAGRAM
NOTE: A = Hardwired connections; D = High speed CAN bus
Anti-Lock Control - Traction ControlLesson 2 – Chassis
153Technical Training (G421079) 

Fusible link 11E, Battery Junction Box (BJB)1
Ignition switch2
Fuse 37P, CJB3
Yaw rate and lateral acceleration sensor4
Fusible link 9E, BJB5
Fusible link 23E, BJB6
Front wheel speed sensor7
Front wheel speed sensor8
Rear wheel speed sensor9
Rear wheel speed sensor10
Navigation computer11
ABS module12
Transmission control module13
Diagnostic socket14
Instrument cluster15
Air suspension control module16
Parking brake module17
Steering angle sensor18
Rear differential control module19
Restraints control...