Contents Wiring diagrams Section: Anti-Lock/traction Control All sections

Anti-Lock Control - Traction Control Land Rover Range Rover L322

Anti-Lock/traction Control 13 illustrations ~6303 words

SPECIFICATION

DescriptionNm
Front wheel speed sensor retaining bolt8
Rear wheel speed sensor retaining bolt8
Anti-lock brake system (ABS) module retaining nuts - up to 10MY8
Brake pipe unions (M10) to ABS module - up to 10MY15
Brake pipe unions (M12) to ABS module - up to 10MY15
Brake pipe unions (M17) to ABS module - up to 10MY17
ABS module retaining nuts - 10MY onwards9
ABS module retaining bolt - 10MY onwards9
Brake pipe unions to ABS module - 10MY onwards18

TORQUE SPECIFICATIONS

Scheme 1

Scheme 1: ANTI-LOCK CONTROL - TRACTION CONTROL - V8 S/C 4.2L PETROL
Item NumberDescription
1Stoplamp switch
2Right rear wheel speed sensor
3Left rear wheel speed sensor
4Yaw rate and lateral acceleration sensor
5Steering angle sensor
6Front left wheel speed sensor
7Front right wheel speed sensor
8Anti-lock brake system (ABS) module
9Hydraulic control unit (HCU)

Note. left-hand drive (LHD) installation shown, right-hand drive (RHD) installation similar

Item NumberDescription
1HDC (hill descent control) information indicator
2Brake warning indicator
3ABS warning indicator
4HDC switch
5DSC (dynamic stability control) switch
6DSC warning indicator

Note. right-hand drive (RHD) installation shown, left-hand drive (LHD) installation similar

GENERAL

The anti-lock control - traction control system is based on the 4 channel Bosch 8.0 system and provides the following brake functions

  1. ARM (active roll mitigation).
  2. Anti-Lock Brake System (ABS).
  3. CBC (corner brake control).
  4. DSC.
  5. Electronic Brake Force Distribution (EBD).
  6. ETC (electronic traction control).
  7. Emergency Brake Assist (EBA).
  8. EDC (engine drag-torque control).
  9. HDC.

The system consists of the following components

  1. A DSC switch.
  2. An HDC switch.
  3. A stoplamp switch.
  4. Four wheel speed sensors.
  5. A yaw rate and lateral acceleration sensor.
  6. A steering angle sensor.
  7. Four warning indicators.
  8. A Hydraulic Control Unit (HCU) with attached Anti-Lock Brake System (ABS) module.

Scheme 2

Scheme 2: DSC SWITCH
Item NumberDescription
1DSC switch

The DSC switch allows the DSC function to be selected off. Although Land Rover recommend that DSC is selected on for all normal driving conditions, it may be beneficial to de-select DSC, to maximize traction, under the following conditions

  1. If the vehicle needs to be rocked out of a hollow or a soft surface.
  2. Driving on loose surfaces or with snow chains.
  3. Driving in deep sand, snow or mud.
  4. On tracks with deep longitudinal ruts.

The DSC switch is a non-latching switch installed in the center switch pack on the instrument panel. Pressing the DSC switch connects an ignition power feed to the anti-lock brake system (ABS) module. With the first press of the DSC switch, the anti-lock brake system (ABS) module disables the DSC functions. When the DSC switch is pressed again, the anti-lock brake system (ABS) module re-enables the DSC functions. The DSC switch must be pressed for a minimum of 0.3 s for the anti-lock brake system (ABS) module to react. The DSC function is re-enabled at the beginning of each ignition cycle.

The status of the DSC switch selection is shown by the DSC warning indicator. The DSC warning indicator is off while DSC is selected on, and continuously illuminated while DSC is selected off.

A DSC switch request to disable DSC is ignored by the anti-lock brake system (ABS) module if the air suspension system has failed, or is in off-road height at speeds above 60 km/h (37.5 mph).

To guard against incorrect operation or a broken switch, if the input from the DSC switch is held high for more than one minute, a failure is stored in the anti-lock brake system (ABS) module.

Even if DSC is deselected, driving maneuvers with extreme yaw or lateral acceleration may trigger DSC activity to assist vehicle stability.

HDC SWITCH

Item NumberDescription
1HDC switch

The HDC switch controls the selection of the HDC function.

The HDC switch is a non-latching switch installed on the center console, to the rear of the gear shift lever. Pressing and releasing the HDC switch momentarily connects an ignition power feed to the anti-lock brake system (ABS) module. With the first press and release of the HDC switch, the anti-lock brake system (ABS) module enables operation of the HDC function. When the HDC switch is pressed and released again, the anti-lock brake system (ABS) module disables operation of the HDC function.

To guard against incorrect operation or a broken switch, if the switch is pressed for more than 10 seconds no change of state occurs. If the input from the HDC switch is held high for more than one minute, a failure is stored in the anti-lock brake system (ABS) module.

STOPLAMP SWITCH

The stoplamp switch is mounted in the brake pedal bracket and operated by the brake pedal. The stoplamp switch is a Hall effect switch with dual status outputs. Both of the outputs are supplied to the anti-lock brake system (ABS) module. One of the outputs is also supplied to the lighting control module (LCM) (to operate the stoplamps) and to the engine control module (ECM).

Power for the stoplamp switch is provided by a feed from the auxiliary contacts of the ignition switch via the central junction box (CJB). The power circuit is completed by a ground connection from the stoplamp switch to a ground header on the body.

When the brake pedal is not pressed, the outputs from the stoplamp switch are low, between 0 and 2 V. When the brake pedal is pressed the outputs are pulled high to between 8 V and battery voltage.

Scheme 3

Scheme 3: WHEEL SPEED SENSORS
Item NumberDescription
1Cable clip
2Hub assembly
3Wheel speed sensor
4Screw

An active wheel speed sensor is installed in each wheel hub to provide the anti-lock brake system (ABS) module with a rotational speed signal from each road wheel. The head of each wheel speed sensor is positioned close to a 48 tooth sensor ring on the outer diameter of the constant velocity joint of the drive halfshaft. A flying lead connects each sensor to the vehicle wiring.

The wheel speed sensors each have a power supply connection and a signal connection with the anti-lock brake system (ABS) module. When the ignition switch is in position II, the anti-lock brake system (ABS) module supplies power to the wheel speed sensors and monitors the return signals. Any rotation of the drive halfshafts induces current fluctuations in the return signals which are converted into individual wheel speeds and the overall vehicle speed by the anti-lock brake system (ABS) module.

The anti-lock brake system (ABS) module outputs the individual wheel speeds and the vehicle speed on the high speed controller area network (CAN) bus for use by other systems. The quality of the vehicle speed signal is also broadcast on the high speed controller area network (CAN) bus. If all wheel speed signals are available to calculate vehicle speed from, the quality of the vehicle speed signal is set to 'data calculated within specified accuracy'. If one or more wheel speed sensors is faulty, the quality of the vehicle speed signal is set to 'accuracy outside specification'.

The anti-lock brake system (ABS) module monitors the wheel speed sensor circuits for faults. If a fault is detected the anti-lock brake system (ABS) module stores a related fault code and illuminates the appropriate warning indicators, depending on the system functions affected (DSC/ETC, ABS, EBA/EBD, HDC). A warning chime sounds and a related message is shown in the message center. Refer to Information and Message Center .

Since the wheel speed sensors are active devices, a return signal is available when the road wheels are not turning, which enables the anti-lock brake system (ABS) module to check the sensors while the vehicle is stationary. In addition, the direction of travel of each wheel can be sensed. This information is broadcast on the high sped controller area network (CAN) bus for use by other systems.

Scheme 4

Scheme 4: YAW RATE AND LATERAL ACCELERATION SENSOR
Item NumberDescription
1Yaw rate and lateral acceleration sensor

Located under the center console, the yaw rate and lateral acceleration sensor provides two inputs to the anti-lock brake system (ABS) module, lateral acceleration and yaw rate, for DSC regulation. The sensor is isolated from body/chassis vibrations through its rubber mounting and secured to the transmission tunnel with 2 bolts.

When the ignition switch is in position II, the yaw rate and lateral acceleration sensor receives an ignition power feed from the central junction box (CJB). For yaw rate, the sensor produces a reference signal of 2.5 volts and a linear yaw rate signal from 0.7 to 4.3 volts. For lateral acceleration, the sensor produces a linear signal from 0.5 to 4.5 volts. In addition to using the inputs for DSC regulation, the anti-lock brake system (ABS) module also broadcasts yaw rate and lateral acceleration values, on the high speed controller area network (CAN) bus, for use by other systems.

The anti-lock brake system (ABS) module monitors the yaw rate and lateral acceleration sensor for faults and can be interrogated using T4. If a fault is detected the anti-lock brake system (ABS) module stores a related fault code and sends a controller area network (CAN) signal to the instrument cluster to illuminate the DSC, HDC and brake warning indicators. The instrument cluster also sounds a warning chime and displays a DSC fault message in the message center. Refer to Information and Message Center .

STEERING ANGLE SENSOR

Item NumberDescription
1Gear wheel
2Electrical connector

The steering angle sensor measures the steering wheel angle and the rate of change of the steering wheel angle (known as the steering wheel angle speed). These measurements are output on the high speed controller area network (CAN) bus, together with a quality factor signal, and used by the anti-lock brake system (ABS) module for CBC and DSC operation.

The steering angle sensor is fixed to the pivot bracket of the steering column by three screws. A gear wheel in the steering angle sensor engages with a plastic drive collar fixed onto the lower shaft of the column. Inside the steering angle sensor, the gear wheel meshes with a gear train containing magnets. An eight pin electrical connector provides the interface between the vehicle wiring and integrated circuits in the steering angle sensor.

The steering angle sensor uses the MR (magneto resistive) effect, which evaluates the direction of magnetic fields, to measure the angular position of the lower shaft, and thus the steering wheel angle. When the steering wheel turns, the steering column lower shaft rotates the gear wheel in the steering angle sensor, which drives the gear train and rotates the magnets on the gears. The direction of the magnetic fields is constantly monitored by the steering angle sensor and converted into a steering wheel angle and steering wheel angle speed.

The steering angle sensor performs a plausibility check of the steering wheel angle each time the following conditions co-exist

  1. The vehicle is traveling in a straight line.
  2. The vehicle speed is between 20 and 25 km/h (12.5 and 15.6 mph).
  3. The transfer box is in high range.
  4. The brake pedal is not pressed.
  5. There is no ABS, DSC or ETC activity.

The steering angle sensor uses inputs of wheel speed, yaw rate and lateral acceleration to determine when the vehicle is traveling in a straight line. When all of the conditions co-exist, the steering angle sensor checks the steering angle, which should be 0 ± 15°. If the steering angle is outside the limits on two successive checks, the steering angle sensor changes the quality factor signal to 'outside specification' for the remainder of the ignition cycle and stores a fault code. At the beginning of each ignition cycle the quality factor signal is reset to 'within specified accuracy'.

The status of the steering angle sensor can be determined using T4.

If the steering angle sensor is replaced, the new sensor must be calibrated using T4. The steering angle sensor must also be re-calibrated any time it is disturbed from the steering column, or if the upper and lower steering columns are separated.

Pin No.DescriptionInput/Output
1 to 4Not used
5Ignition power supplyInput
6High speed CAN bus highInput/Output
7High speed CAN bus lowInput/Output
8Ground

STEERING ANGLE SENSOR HARNESS CONNECTOR C0862 PIN DETAILS

Scheme 5

Scheme 5: WARNING INDICATORS
Item NumberDescription
1HDC information indicator
2Brake warning indicator
3ABS warning indicator
4DSC warning indicator

ANTI-LOCK BRAKE SYSTEM (ABS) WARNING INDICATOR

The anti-lock brake system (ABS) warning indicator is an amber colored indicator located between the coolant temperature gage and the fuel level gage.

The anti-lock brake system (ABS) warning indicator is continuously illuminated if there is a fault that affects anti-lock brake system (ABS) performance or causes the anti-lock brake system (ABS) function to be disabled.

Operation of the anti-lock brake system (ABS) warning indicator is controlled by a high speed controller area network (CAN) bus message from the anti-lock brake system (ABS) module to the instrument cluster. There is no bulb check of the anti-lock brake system (ABS) warning indicator when the ignition is switched on.

If a fault causes the anti-lock brake system (ABS) warning indicator to be illuminated, the anti-lock brake system (ABS) warning indicator may illuminate after the next engine start, even if the fault has been rectified and cleared from the anti-lock brake system (ABS) module. The anti-lock brake system (ABS) warning indicator will then remain illuminated until vehicle speed reaches 15-20 km/h (9.5-12.5 mph) while additional checks of the related inputs are performed.

BRAKE WARNING INDICATOR

The brake warning indicator is a dual colored indicator, located in the coolant temperature gage, that illuminates amber for emergency brake assist (EBA) faults and red for electronic brake force distribution (EBD) faults. The brake warning indicator is also used to give warnings of

  1. Low brake fluid level (illuminates red). Refer to «Hydraulic Brake Actuation»(/land-rover/range-rover/l322-2005-2009/remont/brakes-control-systems/#hydraulic-brake-actuation) .
  2. Brake pad wear (illuminates red). Refer to «Rear Disc Brake»(/land-rover/range-rover/l322-2005-2009/remont/mechanical-hydraulic/#rear-disc-brake) .

Operation of the brake warning indicator, for emergency brake assist (EBA) and electronic brake force distribution (EBD) faults, is controlled by high speed controller area network (CAN) bus messages from the anti-lock brake system (ABS) module to the instrument cluster.

When the ignition switch is first turned to position II, the brake warning indicator illuminates amber for approximately 1 second then red for approximately 1 second, as a bulb check.

DSC WARNING INDICATOR

The DSC warning indicator is an amber colored indicator located in the tachometer.

Each time the DSC or the ETC function is active, the DSC warning indicator flashes at 2 Hz. If DSC has been selected off, or there is a fault that disables the DSC or the ETC function, the DSC warning indicator is continuously illuminated. If DSC has been selected off, vehicles also display a message, advising that DSC is switched off. Refer to Information and Message Center .

Operation of the DSC warning indicator is controlled by a high speed controller area network (CAN) bus message from the anti-lock brake system (ABS) module to the instrument cluster.

When the ignition switch is first turned to position II, the DSC warning indicator illuminates for approximately 2 seconds as a bulb check. If a fault during the previous ignition cycle caused the DSC warning indicator to be illuminated, the DSC warning indicator may remain illuminated after the next bulb check, even if the fault has been rectified and cleared from the anti-lock brake system (ABS) module; the DSC warning indicator may remain illuminated during vehicle operation while additional checks of the related inputs are performed.

HDC INFORMATION INDICATOR

The HDC information indicator is a green colored indicator located in the tachometer.

The HDC information indicator is continuously illuminated while the HDC function is selected on and the vehicle is within the parameters for HDC operation; when the vehicle is outside the parameters for HDC operation, the HDC information indicator is flashed at 2 Hz.

Operation of the HDC information indicator is controlled by a high speed controller area network (CAN) bus message from the anti-lock brake system (ABS) module to the instrument cluster.

When the ignition switch is first turned to position II, the HDC information indicator illuminates for approximately 2 seconds, as a bulb check.

HCU

The hydraulic control unit (HCU) is a 4 channel unit that modulates the supply of hydraulic pressure to the brakes under the control of the anti-lock brake system (ABS) module.

The hydraulic control unit (HCU) is installed in the engine compartment, on three mounting bushes attached to the driver side inner fender. Hydraulic pipes connect the hydraulic control unit (HCU) to the master cylinder and the brakes. Refer to Hydraulic Brake Actuation .

The primary and secondary outlets of the master cylinder are connected to primary and secondary circuits within the hydraulic control unit (HCU). The primary circuit in the hydraulic control unit (HCU) has separate outlet ports to the front brakes. The secondary circuit in the hydraulic control unit (HCU) has separate outlet ports to the rear brakes. Each of the circuits in the hydraulic control unit (HCU) contain the following components to control the supply of hydraulic pressure to the brakes

  1. A normally open, solenoid operated, pilot valve, to enable active braking.
  2. A normally closed, solenoid operated, priming valve, to connect the brake fluid reservoir to the return pump during active braking.
  3. A return pump, to generate hydraulic pressure for active braking and return brake fluid to the reservoir.
  4. Normally open, solenoid operated, inlet valves and normally closed, solenoid operated, outlet valves, to modulate the hydraulic pressure in the individual brakes.
  5. An accumulator and a relief valve, to allow the fast release of pressure from the brakes.
  6. Filters, to protect the components from contamination.

The primary circuit also incorporates a pressure sensor to provide the anti-lock brake system (ABS) module with a hydraulic pressure signal.

Contact pins on the hydraulic control unit (HCU) mate with contacts on the anti-lock brake system (ABS) module to provide the electrical connections from the anti-lock brake system (ABS) module to the return pump motor and the pressure sensor. The solenoids that operate the valves are installed in the anti-lock brake system (ABS) module.

Replacement hydraulic control unit (HCU) are supplied pre-filled. After installation on the vehicle, T4 must be used to operate the solenoid valves and the return pump to ensure correct bleeding of the hydraulic control unit (HCU) and brake circuits.

Item NumberDescription
1Master cylinder
2Reservoir
3Brake booster
4Brake pedal
5HCU
6Pressure sensor
7Priming valve
8Pilot valve
9Return pump motor
10Return pump
11Inlet valve
12Relief valve
13Accumulator
14Outlet valve
15Left front brake
16Right front brake
17Right rear brake
18Left rear brake

The hydraulic control unit (HCU) has three operating modes: Normal braking/electronic brake force distribution (EBD), anti-lock brake system (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 anti-lock brake system (ABS) module determines that electronic brake force distribution (EBD) is necessary, it energizes the inlet valves for the brakes of the trailing axle, to isolate the brakes from any further increase in hydraulic pressure.

ABS BRAKING MODE

If the anti-lock brake system (ABS) module determines that anti-lock brake system (ABS) braking is necessary, it energizes the inlet and outlet valves of the related brake and starts the return pump. The inlet valve closes to isolate the brake from pressurized fluid; the outlet valve opens to release pressure from the brake into the accumulator and the return pump circuit; the reduced pressure allows the wheel to accelerate. The anti-lock brake system (ABS) module then operates the inlet and outlet valves to modulate the pressure in the brake to apply the maximum braking effort without locking the wheel. Control of the valves for each wheel takes place individually.

ACTIVE BRAKING MODE

The active braking mode is used to generate and control hydraulic pressure to the brakes for functions other than anti-lock brake system (ABS) braking, e.g. DSC, EBA, ETC, HDC and dynamic application of the parking brake.

For active braking, the anti-lock brake system (ABS) module energizes the pilot valves and priming valves, starts the return pump and energizes all of the inlet valves. Brake fluid, drawn from the reservoir through the master cylinder and priming valve, is pressurized by the return pump and supplied to the inlet valves. The anti-lock brake system (ABS) module then operates the inlet valves and outlet valves, as required, to modulate the pressure in the individual brakes. Some noise may be generated during active braking.

ABS MODULE

The anti-lock brake system (ABS) module controls the brake functions using the hydraulic control unit (HCU) to modulate hydraulic pressure to the individual wheel brakes.

The anti-lock brake system (ABS) module is attached to the hydraulic control unit (HCU), on the driver side inner fender in the engine compartment. A 46 pin connector provides the electrical interface between the anti-lock brake system (ABS) module and the vehicle wiring.

Pin No.DescriptionInput/Output
1GroundOutput
2Battery power supplyInput
3Battery power supplyInput
4GroundOutput
5Front left wheel speed sensor signalInput
6Rear left wheel speed sensor power supplyOutput
7Rear right wheel speed sensor power supplyOutput
8Rear right wheel speed sensor signalInput
9Front right wheel speed sensor power supplyOutput
10Front right wheel speed sensor signalInput
11Diagnostic ISO 9141 K line busInput/Output
12 and 13Not used
14High speed CAN bus lowInput/Output
15Yaw rate and lateral acceleration sensor groundInput
16Yaw rate signalInput
17Not used
18Yaw rate and lateral acceleration sensor referenceInput
19Not used
20Lateral acceleration signalInput
21Not used
22Lighting Control Module (LCM)Output
23 to 25Not used
26Front left wheel speed sensor power supplyOutput
27Rear left wheel speed sensor signalInput
28Ignition power supplyInput
29Not used
30Stoplamp switchInput
31DSC switchInput
32Not used
33Road speed signalOutput
34Not used
35High speed CAN bus highInput/Output
36HDC switchInput
37Yaw rate and lateral acceleration sensor testOutput
38 to 40Not used
41Stoplamp switchInput
42 to 46Not used

ABS MODULE HARNESS CONNECTOR C1585 PIN DETAILS

ARM

The ARM function uses the brakes and the engine to attempt to restore stability if the vehicle is forced into such a harsh maneuver that it risks tipping over.

The anti-lock brake system (ABS) module monitors driver inputs and vehicle behavior using various powertrain signals and the inputs from the wheel speed sensors, the steering angle sensor and the yaw rate and lateral acceleration sensor. These are compared with modeled behavior and, if vehicle behavior reaches a given risk level, the anti-lock brake system (ABS) module cuts the engine power, or brakes one or more wheels, just enough to help the vehicle regain its poise and help the driver remain in control.

While the ignition is on, ARM is permanently enabled, even when DSC has been selected off.

ABS

anti-lock brake system (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 axle, the brake pressure is modulated separately for each wheel. On the rear axle, brake pressure is modulated by select low. Select low applies the same pressure to both rear brakes, with the pressure level being determined by the wheel on the lower friction surface. This maintains rear stability on split friction surfaces.

CBC

CBC influences the brake pressures, below the DSC and anti-lock brake system (ABS) thresholds, to counteract the yawing moment produced when braking in a corner. CBC produces a correction torque by limiting the brake pressure on one side of the vehicle.

DSC

DSC uses the brakes and powertrain torque control to help maintain the lateral stability of the vehicle. While the ignition is on the DSC function is permanently enabled unless selected off by the DSC switch. Even if DSC is deselected, driving maneuvers with extreme yaw or lateral acceleration may trigger DSC activity to assist vehicle stability.

DSC enhances driving safety in abrupt maneuvers and in understeer or oversteer situations which may occur in a bend. The anti-lock brake system (ABS) module monitors the yaw rate and lateral acceleration of the vehicle, and the steering input, then selectively applies individual brakes and signals for powertrain torque adjustments to reduce understeer or oversteer.

In general: in an understeering situation, the inner wheels are braked to counteract the yaw movement towards the outer edge of the bend; in an oversteering situation, the outer wheels are braked to prevent the rear end of the vehicle from pushing towards the outer edge of the bend.

The anti-lock brake system (ABS) module monitors the tracking stability of the vehicle using inputs from the wheel speed sensors, the steering angle sensor and the yaw rate and lateral acceleration sensor. The tracking stability is compared with stored target data and, whenever the tracking stability deviates from the target data, the anti-lock brake system (ABS) module intervenes by applying the appropriate brakes. On vehicles with an automatic transmission, when the DSC function is active, the anti-lock brake system (ABS) module also signals the transmission control module (TCM) to prevent gear shifts. If necessary, the anti-lock brake system (ABS) module also signals

  1. The engine control module (ECM), to reduce engine torque.
  2. The transfer box control module, to adjust the locking torque of the center differential.
  3. The rear differential control module, to adjust the locking torque of the rear differential.

The DSC function overrides the differential locking torque requests from the terrain response system.

If DSC is selected off, a warning chime sounds and a system off message is shown in the message center. Refer to Information and Message Center .

EBD

electronic brake force distribution (EBD) limits the brake pressure applied to the rear wheels. When the brakes are applied, the weight of the vehicle transfers forwards, which reduces the ability of the rear wheels to transfer braking effort to the road surface. This can cause the rear wheels to slip and make the vehicle unstable.

electronic brake force distribution (EBD) uses the anti-lock braking hardware to automatically optimize the pressure of the rear brakes, below the point where anti-lock braking would be invoked. Only the rear axle is under electronic brake force distribution (EBD) control.

ETC

ETC attempts to optimize forward traction by reducing engine torque or braking a spinning wheel until it regains grip.

ETC is activated if an individual wheel speed is above that of the vehicle reference speed (positive slip) and the brake pedal is not pressed. The spinning wheel is braked, allowing the excess torque to be transmitted to the non spinning wheels through the drive line. If necessary, the anti-lock brake system (ABS) module also sends a high speed controller area network (CAN) bus message to the engine control module (ECM) to request a reduction in engine torque. Torque reduction requests are for either a slow or fast response: a slow response requests a reduction of throttle angle; a fast response requests an ignition cut-off.

When the DSC function is selected off with the DSC switch, the engine torque reduction feature is disabled.

When the ETC function is active the anti-lock brake system (ABS) module also signals the transmission control module (TCM) to prevent gear shifts.

EBA

emergency brake assist (EBA) assists the driver, in emergency braking situations, by automatically maximizing the braking effort. There are two situations when the anti-lock brake system (ABS) module will invoke emergency brake assist (EBA): when the brake pedal is pressed very suddenly and when the brake pedal is pressed hard enough to bring the front brakes into anti-lock brake system (ABS) operation.

When the brake pedal is pressed very suddenly, the anti-lock brake system (ABS) module increases the hydraulic pressure to all of the brakes until they reach the threshold for anti-lock brake system (ABS) operation, thus applying the maximum braking effort for the available traction. The anti-lock brake system (ABS) module monitors for the sudden application of the brakes using the inputs from the stoplamp switch and from the pressure sensor in the hydraulic control unit (HCU). With the brake pedal pressed, if the rate of increase of hydraulic pressure exceeds the predetermined limit, the anti-lock brake system (ABS) module invokes emergency braking.

When the brake pedal is pressed hard enough to bring the front brakes into anti-lock brake system (ABS) operation, the anti-lock brake system (ABS) module increases the hydraulic pressure to the rear brakes up to the anti-lock brake system (ABS) threshold.

emergency brake assist (EBA) operation continues until the driver releases the brake pedal enough for the hydraulic pressure in the hydraulic control unit (HCU) to drop below a threshold value stored in the anti-lock brake system (ABS) module.

EDC

EDC prevents wheel slip caused by any of the following

  1. A sudden decrease in engine torque when the accelerator is suddenly released.
  2. A downshift using the CommandShift™.

When the anti-lock brake system (ABS) module detects the onset of wheel slip without the brakes being applied it signals the engine control module (ECM), on the high speed engine control module (ECM) bus, to request a momentary increase in engine torque.

HDC

HDC uses brake intervention to control vehicle speed and acceleration during low speed descents in off-road and low grip on-road conditions. Generally, equal pressure is applied to all four brakes, but pressure to individual brakes can be modified by the anti-lock brake system (ABS) and DSC functions to retain stability. Selection of the HDC function is controlled by the HDC switch on the center console. HDC operates in both high and low ranges, at vehicle speeds up to 50 km/h (31.3 mph).

HDC may be used in D, R and CommandShift 1 in high range, and in D, R and all CommandShift gears in low range. When in D, the transmission control module will automatically select the most appropriate gear. The vehicle should not be driven with HDC active and the transmission in N.

HDC can be selected at speeds up to 80 km/h (50 mph), but will only be enabled at speeds below 50 km/h (31.3 mph). When HDC is selected

  1. At speeds up to 50 km/h (31.3 mph), the HDC information indicator is permanently illuminated if a valid gear is selected.
  2. At speeds from >50 to 80 km/h (>31.3 to 50 mph) the HDC information indicator flashes and a message advising that the speed is too high is displayed in the message center. Refer to «Information and Message Center»(/land-rover/range-rover/l322-2005-2009/remont/gauges-instrument-panels/#information-and-message-center) . If the HDC switch is pressed while vehicle speed is more than 80 km/h (50 mph), the HDC information indicator will not illuminate and HDC will not be selected.
  3. If the speed increases to 80 km/h (50 mph), the HDC function is switched off, the information indicator goes off, a warning chime sounds and a message advising that HDC has been switched off is displayed in the message center.

When HDC is enabled, the anti-lock brake system (ABS) module calculates a target speed and compares this with the actual vehicle speed. The anti-lock brake system (ABS) module then operates the HCU, in the active braking mode, as required to achieve and maintain the target speed. During active braking for HDC, the anti-lock brake system (ABS) module also energizes the HDC relay to operate the stoplamps. Applying the foot brakes during active braking may result in a pulse through the brake pedal, which is normal.

The target speed varies, between minimum and maximum values for each gear and transmission range, depending on driver input with the accelerator pedal. If the accelerator pedal is not operated, the anti-lock brake system (ABS) module adopts a default target speed.

LimitSpeed, km/h (mph)
Gears 1, RGears D, 2 to 6
Default3.5 (2.19)6 (3.75)
Minimum3.5 (2.19)3.5 (2.19)
Maximum20 (12.5)20 (12.5)

LOW RANGE TARGET SPEEDS

LimitSpeed, km/h (mph)
Gears 1, RGear D
Default6 (3.75)10 (6.25)
Minimum6 (3.75)6 (3.75)
Maximum20 (12.5)20 (12.5)

HIGH RANGE TARGET SPEEDS

As well as varying the target speed with the accelerator pedal, the target speed can also be varied by pressing the speed control '+' and '-' buttons (where fitted). Speed Control.

During changes of target speed, the anti-lock brake system (ABS) module limits deceleration and acceleration to -0.5 m/s 2 (-1.65 ft/s 2 ) and +0.5 m/s 2 (+1.65 ft/s 2 ) respectively.

To provide a safe transition from active braking to brakes off, the anti-lock brake system (ABS) module invokes a fade out strategy, which gradually discontinues the braking effort, if it detects any of the following during active braking

  1. HDC selected off with the HDC switch.
  2. Failure of a component used by HDC, but not critical to the fade out function.
  3. Accelerator pedal pressed when transmission is in neutral.
  4. Brake overheat.

If fade out is invoked because of deselection or component failure, the HDC function is cancelled by the anti-lock brake system (ABS) module. If fade out is invoked because the accelerator pedal is pressed with the transmission in 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/s 2 (1.65 ft/s 2 ), 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/s 2 (3.3 ft/s 2 ).

When fade out is invoked because of component failure, a warning chime sounds, the HDC information indicator is extinguished and a message advising there is a fault is displayed in the message center.

When fade out is invoked because of brake overheat, a message advising that HDC is temporarily unavailable is displayed. At the end of fade out, the HDC information indicator flashes. The message is displayed, while HDC remains selected, until the brakes have cooled.

To monitor for brake overheat, the anti-lock brake system (ABS) module monitors the amount of braking activity and, from this, estimates the temperature of each brake. If the estimated temperature of any brake exceeds a preset limit, the anti-lock brake system (ABS) module invokes the fade out strategy. After the fade out cycle, the HDC function is re-enabled when the anti-lock brake system (ABS) module estimates that all of the brake temperatures are at less than 64% of the temperature limit.

When HDC is selected off, a warning chime sounds and a system off message is shown in the message center. Refer to Information and Message Center .

Scheme 6

Scheme 6: CONTROL DIAGRAM
Item NumberDescription
1HDC warning indicator
2Brake warning indicator
3ECM
4Steering angle sensor
5Fuse 55, CJB
6Diagnostic socket
7Left stoplamp
8Center high mounted stoplamp
9Right stoplamp
10LCM
11Stoplamp switch
12Wheel speed sensor
13Wheel speed sensor
14Wheel speed sensor
15Wheel speed sensor
16Yaw rate and lateral acceleration sensor
17Maxi fuse 63, CJB
18HDC switch
19Fuse 38, CJB
20Ignition switch
21Fuse 35, CJB
22ABS module
23DSC switch
24ABS warning indicator
25DSC warning indicator
26Instrument cluster

Note. A = Hardwired connections; D = High speed controller area network (CAN) bus; J = Diagnostic ISO9141 K line bus

INSPECTION AND VERIFICATION

CAUTIONDiagnosis by substitution from a donor vehicle is NOT acceptable. Substitution of control modules does not guarantee confirmation of a fault and may also cause additional faults in the vehicle being checked and/or the donor vehicle.

Note. If the control module or a component is suspect and the vehicle remains under manufacturer warranty, refer to the Warranty Policy and Procedures information (instructions B1.2), or determine if any prior approval program is in operation, prior to the installation of a new module/component.

Note. Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.

  1. Verify the customer concern.
  2. Visually inspect for obvious signs of mechanical or electrical damage. Mechanical Electrical Tire size, condition and installation Wheel speed sensor condition and installation Steering Angle Sensor (SAS) condition and installation Yaw rate sensor and accelerometer condition and installation Hydraulic control unit (with attached ABS module) condition and installation Fuses Harnesses and connectors Warning lamp operation Wheel speed sensors Central junction box HDC switch DSC switch Combined stop lamp switch / brake switch Yaw rate sensor and accelerometer Steering Angle Sensor (SAS) Anti-lock Braking (ABS) module Controller Area Network (CAN) circuits
  3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
  4. If the cause is not visually evident, check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.

DTC INDEX

Note. Generic scan tools may not read the codes listed, or may read only 5-digit codes. Match the 5 digits from the scan tool to the first 5 digits of the 7-digit code listed to identify the fault (the last 2 digits give extra information read by the manufacturer-approved diagnostic system).

DTCDescriptionPossible CausesAction
C1105-67Brake lamp control signal incorrect after event - signal incorrect after eventNOTE: The stoplamp-switch contains the brake-lamp -switch (BLS) and the brake-switch (BS) these are located within the same housing The BLS circuit and the BS circuit have failed the plausibility test Switch internal fault Circuit faultNOTE: Check for correct operation of the stop-lamps Refer to the electrical circuit diagrams and check the ABS module circuit to the hill decent relay for fault
C1109-24Vehicle dynamics control switch - signal stuck highSwitch internal fault Circuit short to powerNOTE: This DTC may be logged if the switch state is active for over 1 minute Check for correct switch operation. Refer to the electrical circuit diagrams and check the ABS module circuit to the center facia switch pack / DSC switch for circuit short to power
C1A00-16Control module - circuit voltage below thresholdLow voltage detected Circuit short to ground, open circuit or high resistanceNOTE: DTC may be stored due to a vehicle charging or starting fault Using the manufacturer approved diagnostic system check other modules for related DTCs. Check for correct vehicle battery / charging system operation. Refer to the electrical circuit diagrams and check the ABS module power (UZ) and ground circuit for fault
C1A00-17Control module - circuit voltage above thresholdVoltage detected above preset maximumNOTE: DTC may be stored due to battery charger use or vehicle charging fault Using the manufacturer approved diagnostic system check other modules for related DTCs. Check for correct vehicle battery and charging system operation
C1A00-1CControl module - circuit voltage out of rangeMomentary low voltage detectedNOTE: DTC may be stored due to a vehicle charging or starting fault Using the manufacturer approved diagnostic system check other modules for related DTCs. Check for correct vehicle charging system operation. Refer to the electrical circuit diagrams and check the ABS module power (UZ) and ground circuit for fault
C1A00-45Control module - program memory failureModule internal faultUsing the manufacturer approved diagnostic system. Clear the DTC and retest if the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A00-46Control module - calibration / parameter memory failureIncorrect car configuration file (CCF) data received from IPC or CCF incorrectly configured Module installed to unrecognized vehicle configuration Module calibration/parameter memory failure (internal error)Configure the module using the approved diagnostic system. Clear the DTC and check if the DTC resets after ignition reset following >10 seconds ignition on. If the possible causes listed have been checked and the DTC persists, suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A00-49Control module - internal electronic failureModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns, suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A00-4AControl module - incorrect component installedThe stored vehicle variant code in the control module (EEPROM) does not match the variant code received via the CAN busUsing the manufacturer approved diagnostic system, confirm that the stored vehicle variant code and the transmitted variant code match. Configure as required
C1A00-4BControl module - over temperatureThe control module has excited a preset maximum temperature Module internal faultNOTE: Investigate the cause of the control module temperature event Using the manufacturer approved diagnostic system, clear the DTC and retest. If DTC returns suspect an internal fault with the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A00-68Control module - event informationControl module event informationUsing the manufacturer approved diagnostic system, check for DTCs relating to a defective steering angle sensor, wheel speed sensor or yaw rate sensor. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A00-88Control module - bus offCAN bus circuit faultUsing the manufacturer approved diagnostic system, carry out the CAN network integrity test. Refer to the electrical circuit diagrams and check the CAN bus circuit to the ABS module for circuit short to power, short to ground, open circuit or high resistance
C1A76-01Valve relay circuit - general electrical failureModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If DTC returns suspect an internal fault with the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A76-04Valve relay circuit - general electrical failureModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If DTC returns suspect an internal fault with the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A77-16Valve relay circuit - circuit voltage below thresholdLow voltage detected Circuit faultNOTE: DTC may be stored due to a vehicle charging or starting fault Using the manufacturer approved diagnostic system, check other modules for related DTCs. Check for correct vehicle charging system operation. Refer to the electrical circuit diagrams and check the ABS module (UBVR) power and ground circuits for fault
C1A78-04Front left inlet valve - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A79-04Front left outlet valve - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A80-04Front right inlet valve - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A81-04Front right outlet valve - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A82-04Rear left inlet valve - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A83-04Rear left outlet valve - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A84-04Rear right inlet valve - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A85-04Rear right outlet valve - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A86-04Commutation valve #1 - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A87-04Commutation valve #2 - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A88-04High pressure switching valve #1 - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A89-04High pressure switching valve #2 - system internal failuresModule internal faultUsing the manufacturer approved diagnostic system, clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A90-12Wheel speed sensor supply circuit - circuit short to batteryWheel speed sensor supply circuit short to powerRefer to the electrical circuit diagrams and check the wheel speed sensor supply (WP) circuit from the ABS module for short to power
C1A91-13Front left wheel speed sensor circuit - circuit openOpen circuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front left wheel speed sensor for open circuit
C1A91-25Front left wheel speed sensor circuit - signal shape / waveform failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front left wheel speed sensor for fault
C1A91-2FFront left wheel speed sensor circuit - signal erraticCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front left wheel speed sensor for fault
C1A91-36Front left wheel speed sensor circuit - signal frequency too lowCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front left wheel speed sensor for fault
C1A91-38Front left wheel speed sensor circuit - signal frequency incorrectFront left wheel speed sensor reluctor ring damagedVisually inspect the front left wheel speed sensor reluctor ring for damage. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A91-62Front left wheel speed sensor circuit - signal compare failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front left wheel speed sensor for fault
C1A91-64Front left wheel speed sensor circuit - signal plausibility failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front left wheel speed sensor for fault
C1A91-65Front left wheel speed sensor circuit - signal has too few transitions / eventsCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front left wheel speed sensor for fault
C1A91-78Front left wheel speed sensor circuit - alignment or adjustment incorrectFront left wheel speed sensor to reluctor ring air gap incorrectCheck and correct the front left wheel speed sensor reluctor ring air gap
C1A92-13Rear left wheel speed sensor circuit - circuit openOpen circuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear left wheel speed sensor for open circuit
C1A92-25Rear left wheel speed sensor circuit - signal shape / waveform failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear left wheel speed sensor for fault
C1A92-2FRear left wheel speed sensor circuit - signal erraticCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear left wheel speed sensor for fault
C1A92-36Rear left wheel speed sensor circuit - signal frequency too lowCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear left wheel speed sensor for fault
C1A92-38Rear left wheel speed sensor circuit - signal frequency incorrectRear left wheel speed sensor reluctor ring damagedVisually inspect the rear left wheel speed sensor reluctor ring for damage. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A92-62Rear left wheel speed sensor circuit - signal compare failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear left wheel speed sensor for fault
C1A92-64Rear left wheel speed sensor circuit - signal plausibility failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear left wheel speed sensor for fault
C1A92-65Rear left wheel speed sensor circuit - signal has too few transitions / eventsCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear left wheel speed sensor for fault
C1A92-78Rear left wheel speed sensor circuit - alignment or adjustment incorrectRear left wheel speed sensor to reluctor ring air gap incorrectCheck and correct the rear left wheel speed sensor reluctor ring air gap
C1A93-13Rear right wheel speed sensor circuit - circuit openOpen circuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear right wheel speed sensor for open circuit
C1A93-25Rear right wheel speed sensor circuit - signal shape / waveform failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear right wheel speed sensor for fault
C1A93-2FRear right wheel speed sensor circuit - signal erraticCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear right wheel speed sensor for fault
C1A93-36Rear right wheel speed sensor circuit - signal frequency too lowCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear right wheel speed sensor for fault
C1A93-38Rear right wheel speed sensor circuit - signal frequency incorrectRear left wheel speed sensor reluctor ring damagedVisually inspect the rear right wheel speed sensor reluctor ring for damage. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A93-62Rear right wheel speed sensor circuit - signal compare failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear right wheel speed sensor for fault
C1A93-64Rear right wheel speed sensor circuit - signal plausibility failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear right wheel speed sensor for fault
C1A93-65Rear right wheel speed sensor circuit - signal has too few transitions / eventsCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the rear right wheel speed sensor for fault
C1A93-78Rear right wheel speed sensor circuit - alignment or adjustment incorrectRear left wheel speed sensor to reluctor ring air gap incorrectCheck and correct the rear right wheel speed sensor reluctor ring air gap
C1A94-13Front right wheel speed sensor circuit - circuit openOpen circuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front right wheel speed sensor for open circuit
C1A94-25Front right wheel speed sensor circuit - signal shape / waveform failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front right wheel speed sensor for fault
C1A94-2FFront right wheel speed sensor circuit - signal erraticCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front right wheel speed sensor for fault
C1A94-36Front right wheel speed sensor circuit - signal frequency too lowCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front right wheel speed sensor for fault
C1A94-38Front right wheel speed sensor circuit - signal frequency incorrectFront right wheel speed sensor reluctor ring damagedVisually inspect the front right wheel speed sensor reluctor ring for damage. Replace as required. Refer to the new module / component installation note at the top of the DTC index
C1A94-62Front right wheel speed sensor circuit - signal compare failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front right wheel speed sensor for fault
C1A94-64Front right wheel speed sensor circuit - signal plausibility failureCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front right wheel speed sensor for fault
C1A94-65Front right wheel speed sensor circuit - signal has too few transitions / eventsCircuit fault Sensor internal failure Module internal faultRefer to the electrical circuit diagrams and check the circuit between the ABS module and the front right wheel speed sensor for fault
C1A94-78Front right wheel speed sensor circuit - alignment or adjustment incorrectFront right wheel speed sensor to reluctor ring air gap incorrectCheck and correct the front right wheel speed sensor reluctor ring air gap
C1A95-4AWheel speed sensor circuit - incorrect component installedIncorrect wheel speed sensor installedCheck the correct wheel speed sensor is installed to vehicle specification
C1A95-62Wheel speed sensor circuit - signal compare failureIncorrectly oriented wheel speed sensorLocate for the incorrectly orientated wheel speed sensor. Remove and relocate correctly
C1A95-64Wheel speed sensor circuit - signal plausibility failureMultiple circuit faults Multiple sensor internal failures Multiple module internal failuresRefer to the electrical circuit diagrams and check the ABS module circuit to the wheel speed sensors for multiple circuit or sensor internal failures. If no individual sensor or circuit faults are evident replace the 4 wheel speed sensors. Refer to the warranty policy and procedures information if a module / component is suspect
C1A96-24Brake light switch circuit - signal stuck highStoplamp-switch (BLS) signal is Active (1) (Footbrake pedal pressed condition) for more than 60 seconds while the vehicle is not braking Stoplamp-switch circuit fault Stoplamp-switch internal fault Stoplamp-switch incorrect installation Stoplamp-switch incorrectly adjustedRefer to the electrical circuit diagrams and check the ABS module circuit to the stoplamp switch for circuit short to power
C1A96-62Brake light switch circuit - signal compare failureSignal compare failure the stoplamp-switch (BLS) and the brake-switch (BS) have shared the same output state at the same time Stoplamp-switch circuit fault Stoplamp-switch internal faultRefer to the electrical circuit diagrams and check the ABS module circuit to the stoplamp switch for circuit for fault
C1A96-64Brake light switch circuit - signal plausibility failureSignal plausibility failure the brake fluid hydraulic pressure (PS) has exceeded 10bar and the stoplamp-switch output state has not switched from Inactive (0) to Active (1) (Footbrake pedal pressed condition) Stoplamp-switch Circuit fault Stoplamp-switch internal fault Stoplamp-switch incorrect installation Stoplamp-switch incorrectly adjustedNOTE: Check for pressure sensor DTCs C1A99-01 or C1A99-49. If either of these DTCs has been stored carry out the specified action prior to investigating DTC C1A96-64 Refer to the electrical circuit diagrams and check the ABS module circuit to the stoplamp switch for circuit for fault
C1A97-24Lateral accelerometer circuit - signal stuck highThe signal from the yaw rate sensor is greater than expected when the vehicle is stationary Circuit short to powerRefer to the electrical circuit diagrams and check the anti-lock (ABS) control module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A97-27Lateral accelerometer circuit - signal rate of change above thresholdThe signal from the yaw rate sensor is above the preset maximumRefer to the electrical circuit diagrams and check the anti-lock (ABS) control module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A97-28Lateral accelerometer circuit - signal bias level out of range / zero adjustment failureYaw rate sensor signal bias level out of range / zero adjustment failureRefer to the electrical circuit diagrams and check the anti-lock (ABS) control module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A97-29Lateral accelerometer circuit - signal invalidThe value from the yaw rate sensor is invalidNOTE: Driving conditions such as driving in circles or a banked track may cause the DTC to log Confirm that driving style has not caused the DTC to log. Using the manufacturer approved diagnostic system. Clear the DTC and retest. Refer to the electrical circuit diagrams and check the anti-lock (ABS) control module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A97-49Lateral accelerometer circuit - internal electronic failureCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the anti-lock (ABS) control module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A97-64Lateral accelerometer circuit - signal plausibility failureCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-08Yaw rate sensor circuit - bus signal / message failuresCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-22Yaw rate sensor circuit - signal amplitude > maximumCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-28Yaw rate sensor circuit - signal bias level out of range / zero adjustment failureCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-29Yaw rate sensor circuit - signal invalidCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-61Yaw rate sensor circuit - signal calculation failureCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-62Yaw rate sensor circuit - signal compare failureCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-64Yaw rate sensor circuit - signal plausibility failureCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-86Yaw rate sensor circuit - signal invalidCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-87Yaw rate sensor circuit - missing messageCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-92Yaw rate sensor circuit - performance or incorrect operationCircuit fault Sensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A98-95Yaw rate sensor circuit - incorrect assemblyIncorrect component installedConfirm the correct yaw rate sensor. is installed to vehicle specification
C1A98-96Yaw rate sensor circuit - component internal failureSensor internal failureRefer to the electrical circuit diagrams and check the ABS module CAN bus circuit to the yaw rate sensor. Check the power and ground supply circuits to the yaw rate sensor also check the installation and location for security
C1A99-01Pressure sensor circuit - general electrical failureABS module internal failureUsing the manufacturer approved diagnostic system clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the warranty policy and procedures information if a module / component is suspect
C1A99-49Control module - internal electronic failureABS module internal failureUsing the manufacturer approved diagnostic system clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the warranty policy and procedures information if a module / component is suspect
C1B00-27Steering angle sensor -signal rate of change above thresholdSteering angle sensor internal failureUsing the manufacturer approved diagnostic system, check the steering angle sensor module for related stored DTCs
C1B00-29Steering angle sensor - signal invalidSteering angle sensor internal failureUsing the manufacturer approved diagnostic system, check the steering angle sensor module for related stored DTCs
C1B00-61Steering angle sensor - signal calculation failureSteering angle sensor internal failureUsing the manufacturer approved diagnostic system, check the steering angle sensor module for related stored DTCs
C1B00-64Steering angle sensor - signal plausibility failureSteering angle sensor internal failureUsing the manufacturer approved diagnostic system, check the steering angle sensor module for related stored DTCs
C1B00-92Steering angle sensor - performance or incorrect operationSteering angle sensor internal failureUsing the manufacturer approved diagnostic system, check the steering angle sensor module for related stored DTCs
C1B02-01Return pump circuit - general electrical failureABS module internal failureSuspect the ABS module. Replace as required. Refer to the warranty policy and procedures information if a module / component is suspect
C1B02-16Return pump circuit - circuit voltage below thresholdReturn pump circuit voltage below thresholdRefer to the electrical circuit diagrams and check the ABS module for battery voltage at the fused supply (UBMR) circuit
C1B02-49Return pump circuit - internal electronic failureABS module internal failureUsing the manufacturer approved diagnostic system clear the DTC and retest. If the DTC returns suspect the ABS module. Replace as required. Refer to the warranty policy and procedures information if a module / component is suspect
C1B22-24Hill descent switch - signal stuck highCircuit short to powerNOTE: This DTC may be logged if the switch is pressed for over 1 minute Check for correct hill decent switch operation. Refer to the electrical circuit diagrams and check the Centre-console switch-pack / Hill-decent Switch circuit for short to power
C2009-95Front axle wheel speed sensors swapped - incorrect assemblyIncorrect component installedCorrectly relocate the front wheel speed sensors
C200A-95Rear axle wheel speed sensors swapped - incorrect assemblyIncorrect component installedCorrectly relocate the rear wheel speed sensors
U0100-87Lost communication with ECM/PCM "A" - missing messageMissing message from the engine control moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the engine control module for related stored DTCs
U0101-87Lost communication with TCM - missing messageMissing message from the transmission control moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the transmission control module for related stored DTCs
U0102-87Lost communication with transfer case control module - missing messageMissing message from the transfer case control moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the transfer case control module for related stored DTCs
U0104-87Lost communication with cruise control module - missing messageMissing message from the adaptive cruise control moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the adaptive cruise control module for related stored DTCs
U0126-87Lost communication with steering angle sensor module - missing messageMissing message from the steering angle sensor moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the steering angle sensor module for related stored DTCs
U0128-87Lost communication with park brake control module - missing messageMissing message from the park brake control moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the park brake control module for related stored DTCs
U0132-87Lost communication with ride level control module - missing messageMissing message from the air suspension control moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the air suspension control module for related stored DTCs
U0133-87Lost communication with active roll control module - missing messageMissing message from the dynamic response moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the dynamic response module for related stored DTCs
U0136-87Lost communication with differential control module - rear - missing messageMissing message from the rear differential control moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the rear differential control module for related stored DTCs
U0138-87Lost communication with all terrain control module - missing messageMissing message from the terrain response control moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the terrain response control module for related stored DTCs
U0155-87Lost communication with instrument panel cluster (IPC) control module - missing messageMissing message from the instrument panel cluster control moduleRefer to the electrical circuit diagrams and check the power, ground and CAN bus connections to the module. Using the manufacturer approved diagnostic system, complete a CAN network integrity test. Check the instrument panel cluster control module for related stored DTCs
U0401-68Invalid data received from ECM/PCM - event informationInvalid data received from the engine control moduleUsing the manufacturer approved diagnostic system check the engine control module for related stored DTCs
U0402-68Invalid data received from transmission control module - event informationInvalid data received from the transmission control moduleUsing the manufacturer approved diagnostic system check the transmission control module for related stored DTCs
U0403-68Invalid data received from transfer case control module - event informationInvalid data received from the transfer case control moduleUsing the manufacturer approved diagnostic system check the transfer case control module for related stored DTCs
U0405-68Invalid data received from cruise control module - event informationInvalid data received from the adaptive cruise control moduleUsing the manufacturer approved diagnostic system check the adaptive cruise control module for related stored DTCs
U0417-68Invalid data received from park brake control module - event informationInvalid data received from the park brake control moduleUsing the manufacturer approved diagnostic system check the park brake control module for related stored DTCs
U0421-68Invalid data received from ride level control module - event informationInvalid data received from the air suspension control moduleUsing the manufacturer approved diagnostic system check the air suspension control module for related stored DTCs
U0428-68Invalid data received from steering angle sensor module - event informationInvalid data received from the steering angle sensor moduleUsing the manufacturer approved diagnostic system check the steering angle sensor module for related stored DTCs
U1A49-68Invalid data received from all terrain control module - event informationInvalid data received from the terrain response control moduleUsing the manufacturer approved diagnostic system check the terrain response control module for related stored DTCs
U1A4A-68Invalid data received from differential control module - rear - event informationInvalid data received from the rear differential control moduleUsing the manufacturer approved diagnostic system check the rear differential control module for related stored DTCs
U2001-68Reduced system function - event informationNOTE: Not a fault condition. System operation suspended while system cools. Customer may have seen the warning lamp illuminated during a period of reduced functionality or may have noticed the vehicle behaving differently in relation to a traction control event Event informationNOTE: This DTC is stored if the control module reduces the level of functionality, to prevent over-heating of the foundation brakes. This is a normal function of the ECU and is not a fault Clear / ignore this DTC
U3000-55Control module - not configuredMismatch with master configure IDCheck the correct ABS module is installed to vehicle specification. Check that the Central Broadcast VIN matches the vehicle VIN. Refit the original module or replace as required
NOTE
The stoplamp-switch contains the brake-lamp -switch (BLS) and the brake-switch (BS) these are located within the same housing
NOTE
Check for correct operation of the stop-lamps
NOTE
This DTC may be logged if the switch state is active for over 1 minute
NOTE
DTC may be stored due to a vehicle charging or starting fault
NOTE
DTC may be stored due to battery charger use or vehicle charging fault
NOTE
DTC may be stored due to a vehicle charging or starting fault
NOTE
Investigate the cause of the control module temperature event
NOTE
DTC may be stored due to a vehicle charging or starting fault
NOTE
Check for pressure sensor DTCs C1A99-01 or C1A99-49. If either of these DTCs has been stored carry out the specified action prior to investigating DTC C1A96-64
NOTE
Driving conditions such as driving in circles or a banked track may cause the DTC to log
NOTE
This DTC may be logged if the switch is pressed for over 1 minute
NOTE
Not a fault condition. System operation suspended while system cools. Customer may have seen the warning lamp illuminated during a period of reduced functionality or may have noticed the vehicle behaving differently in relation to a traction control event
NOTE
This DTC is stored if the control module reduces the level of functionality, to prevent over-heating of the foundation brakes. This is a normal function of the ECU and is not a fault

REMOVAL

CAUTIONMake sure the ignition switch is in position 0.

Note. The hydraulic control unit (HCU) mounted to the ABS module cannot be serviced separately. If the HCU requires replacement, then the ABS module must be replaced as a complete assembly.

Scheme 7

Scheme 7

Scheme 8

Scheme 8

Scheme 9

Scheme 9
  1. Raise and support the vehicle.
  2. Disconnect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#battery-mounting-and-cables) .
  3. Disconnect the electrical connector. Release the latch. Reposition the electrical connector.
  4. Release the 6 brake fluid lines. Position an absorbent cloth to collect fluid spillage.
  5. Remove the ABS module. Loosen but do not remove the 2 nuts. Release from the locating grommet.

INSTALLATION

  1. Install the ABS module. Tighten the nuts to 8 Nm (6 lb.ft). Tighten the M10 and M12 unions to 15 Nm (11 lb.ft). Tighten the M14 union to 17 Nm (13 lb.ft).
  2. Connect the electrical connector. Secure the latch.
  3. Connect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#battery-mounting-and-cables) .
  4. Bleed the brake system. Refer to «Brake System Bleeding - Vehicles With: Standard Brakes»(/land-rover/range-rover/l322-2005-2009/remont/anti-locktraction-control/#brake-system-general-information__brake-system-bleeding-vehicles-with-standard) .
CAUTIONMake sure the ignition switch is in position 0.

Note. The hydraulic control unit (HCU) mounted to the ABS module cannot be serviced separately. If the HCU requires replacement, then the ABS module must be replaced as a complete assembly.

  1. Raise and support the vehicle.
  2. Disconnect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#battery-mounting-and-cables) .
  3. Disconnect the electrical connector. Release the latch. Reposition the electrical connector.
  4. Release the 6 brake fluid lines. Position an absorbent cloth to collect fluid spillage.
  5. Remove the ABS module. Loosen but do not remove the 2 nuts. Release from the locating grommet.
  1. Install the ABS module. Tighten the nuts to 8 Nm (6 lb.ft). Tighten the M10 and M12 unions to 15 Nm (11 lb.ft). Tighten the M14 union to 17 Nm (13 lb.ft).
  2. Connect the electrical connector. Secure the latch.
  3. Connect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#battery-mounting-and-cables) .
  4. Bleed the brake system. Refer to «Brake System Bleeding - Vehicles With: High Performance Brakes»(/land-rover/range-rover/l322-2005-2009/remont/anti-locktraction-control/#brake-system-general-information__brake-system-bleeding-vehicles-with-high) .
CAUTIONMake sure the ignition switch is in the OFF position.

Note. The hydraulic control unit (HCU) mounted to the Anti-lock Brake System (ABS) module cannot be serviced separately. If the HCU requires replacement, then the ABS module must be replaced as a complete assembly.

  1. Raise and support the vehicle.
  2. Disconnect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#charging-system-general-information__specifications) .
  3. Disconnect the electrical connector. Release the latch. Move the electrical connector aside.
  4. Release the 6 brake fluid lines. Position an absorbent cloth to collect fluid spillage.
  5. Remove the ABS module. Loosen but do not remove the 2 nuts. Release from the locating grommet.
  1. Install the ABS module. Tighten the nuts to 8 Nm (6 lb.ft). Tighten the M10 and M12 unions to 15 Nm (11 lb.ft). Tighten the M14 union to 17 Nm (13 lb.ft).
  2. Connect the electrical connector. Secure the latch.
  3. Connect the battery ground cable. Refer to «Specifications»(/land-rover/range-rover/l322-2005-2009/remont/charging-system/#charging-system-general-information__specifications) .
  4. Bleed the brake system. Refer to «Brake System Bleeding - Vehicles With: High Performance Brakes»(/land-rover/range-rover/l322-2005-2009/remont/anti-locktraction-control/#brake-system-general-information__brake-system-bleeding-vehicles-with-high) .

Scheme 10

Scheme 10: REMOVAL

Scheme 11

Scheme 11
  1. Raise and support the vehicle.
  2. Remove the wheel and tire.
  3. Disconnect the wheel speed sensor electrical connector. Open the electrical connector housing. Release the electrical connector from the clip.
  4. Release the front wheel speed sensor wiring harness.
  5. Remove the front wheel speed sensor. Release the clip. Remove the bolt.
  1. Install the front wheel speed sensor. Apply anti-seize compound to the wheel speed sensor. Tighten the bolt to 8 Nm (6 lb.ft) Secure the clip.
  2. Secure the front wheel speed sensor wiring harness. Connect the wheel speed sensor electrical connector. Secure the electrical connector in the clip. Close the electrical connector housing.
  3. Install the wheel and tire. Tighten the wheel nuts to 140 Nm (103 lb.ft).
  4. Using the approved Land Rover diagnostic system, clear the fault codes from the anti-lock brake system (ABS) module.

Scheme 12

Scheme 12: REMOVAL

Scheme 13

Scheme 13
  1. Raise and support the vehicle.
  2. Remove the wheel and tire.
  3. Release the wheel arch liner. Remove the 5 screws.
  4. Disconnect the rear wheel speed sensor electrical connector. Open the electrical connector housing. Release the electrical connector from the clip.
  5. Remove the rear wheel speed sensor. Release the wiring harness from the 5 clips. Remove the bolt.
  1. Install the rear wheel speed sensor. Apply anti-seize compound to the ABS sensor. Secure the wiring harness in the clips. Tighten the bolt to 8 Nm (6 lb.ft)
  2. Connect the wheel speed sensor electrical connector. Secure the electrical connector clip. Close the electrical connector housing.
  3. Secure the wheel arch liner. Tighten the screws.
  4. Install the wheel and tire. Tighten the wheel nuts to 140 Nm (103 lb.ft).
  5. Using the approved Land Rover diagnostic system, clear the fault codes from the ABS ECU.