Jeep WK2 Grand Cherokee Anti-Lock Brake System (ABS)

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Welcome to the In-Depth web page on the WK2 Jeep Grand Cherokee anti lock brake system. Did we miss something? get in contact with us and tell us!

The Antilock Brake System (ABS) is an electronically operated, 4 channel brake management system which is a part of Electronic Stability Control (ESC) together with Electronic Roll Mitigation (ERM). The car additionally has Electronic Variable Brake Proportioning (EVBP) designed into the system which eliminates the mix/proportioning valve. The mixed Hydraulic Control Unit (HCU) and ABS module is situated ahead of the grasp cylinder, beneath the engine air field.

The system is designed to forestall wheel lockup and keep steering management throughout braking. Preventing lockup is achieved by modulating fluid strain to the wheel brake items.

The hydraulic system is a 4 channel design. All wheel brakes are managed individually. The ABS electrical system is separate from different electrical circuits within the car. The ABS module operates the system elements.

ABS system main elements embrace:

  • Antilock Brake Module (ABM) – The ABS module is mounted to the Hydraulic Control Unit and operates the ABS. The mixed HCU and ABS module is situated ahead of the grasp cylinder, beneath the engine air field. If the Antilock Brake System module is changed it should be initialized utilizing the scan software.
  • Hydraulic Control Unit (HCU) – The Hydraulic Control Unit consists of a valve physique, pump motor, and inlet/retailers for the brake traces. The mixed HCU and Antilock Brake System (ABS) module is situated ahead of the grasp cylinder, beneath the engine air field.
  • Wheel Speed Sensors (WSS) – A wheel pace sensor is used at every wheel. The entrance sensors are mounted to the steering knuckles.
  • ABS Warning Light
  • Dynamics Sensor – The Dynamics Sensor features a yaw price sensor. The yaw price, lateral acceleration and longitudinal acceleration sensors are housed into one unit referred to as the dynamics sensor. The sensor is used to measure car rotational sensing (how briskly the car is popping – yaw), side-to-side (lateral) movement and longitudinal acceleration (ahead). The dynamics sensor has one electrical connector and is situated on the ground panel transmission tunnel beneath the middle ground console, in entrance of the Occupant Restraint Controller (ORC) module.
  • Steering Angle Sensor (SAS) – The SAS is a part of the Steering Control Module (SCM) within the steering column. Under transient cornering situations the lateral acceleration sensor doesn’t measure the true facet to facet drive on the automobile. In order to compensate for this the system makes use of the Steering Angle Sensor (SAS) and car pace to estimate the true sway drive. This sign is matched with the lateral acceleration sensor sign to make sure a significantly-reduced transient facet to facet drive of the car physique.
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Battery voltage is equipped to the Antilock Brake System (ABS) module. The ABS module performs a system initialization process at begin up together with an ABS motor examine. Initialization consists of a static and dynamic self examine of system electrical elements.

The static and dynamic checks happens at ignition begin up. During the dynamic examine, the ABS module briefly cycles solenoids to confirm operation. An audible noise could also be heard throughout this self examine. This noise must be thought of regular.

If an ABS element reveals a fault throughout initialization, the ABS module illuminates the amber warning mild and registers a fault code within the microprocessor reminiscence.

The ABS module displays wheel pace sensor inputs constantly whereas the car is in movement. However, the ABS module is not going to activate any ABS elements so long as sensor inputs point out regular braking.

During regular braking, the grasp cylinder, energy booster and wheel brake items all perform as they’d in a car with out ABS. The Hydraulic Control Unit (HCU) elements are usually not activated.

The goal of the antilock system is to forestall wheel lockup. Preventing lockup helps keep car braking motion and steering management.

The ABS module prompts the system each time sensor indicators point out durations of wheel slip.

The antilock system prevents lockup throughout a wheel slip situation by modulating fluid apply strain to the wheel brake items.

Brake fluid apply strain is modulated in response to wheel pace, diploma of slip and price of deceleration. Sensors at every wheel convert wheel pace into electrical indicators. These indicators are transmitted to the ABS module for processing and willpower of wheel slip and deceleration price.

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The ABS system has 4 fluid strain management channels. Each wheel brakes are managed individually. A pace sensor enter sign indicating a wheel slip situation prompts the ABS module antilock program.

There are Two solenoid valves (Isolation and Dump valve) that are utilized in every antilock management channel. The valves are all situated inside the HCU valve physique and work in pairs to both enhance, maintain, or lower apply strain as wanted within the particular person management channels.

During an ABS cease the ISO valve is energized which acts to forestall additional strain build-up to the calipers. Then the Dump valve dumps off strain till the wheel unlocks. This will proceed till the wheels give up slipping altogether.


This system anticipates the potential for wheel carry by monitoring the motive force’s steering wheel enter and the pace of the car. When ERM determines that the speed of change of the steering wheel angle and automobiles pace are enough to doubtlessly trigger wheel carry, it applies the suitable brake and should cut back engine energy to minimize the prospect that wheel carry will happen. ERM will solely intervene throughout very extreme or evasive driving maneuvers.

ERM can solely cut back the prospect of wheel carry occurring throughout extreme or evasive driving maneuvers. It cannot stop wheel carry resulting from different components similar to highway situations, leaving the roadway or hanging objects or different automobiles.


Ready Alert Braking is a characteristic that applies very low brake strain to all calipers after a fast accelerator pedal launch is detected. This characteristic gives a agency assured pedal really feel and optimum stopping distance within the case of fast accelerator launch.

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The Rain Brake Support is a characteristic that removes the water movie that builds up between the pads and the rotors when driving in moist situations. When the windshield wipers are energetic, this characteristic applies a really low brake strain to all calipers periodically. This maintains a agency, assured brake pedal really feel and optimum stopping distance in moist situations.

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