Jeep Liberty: Electronic Brake Control System

Your vehicle is equipped with an advanced electronic brake control system commonly referred to as ESC. This system includes Anti-Lock Brake System (ABS), Traction Control System (TCS), Brake Assist System (BAS), Hill Start Assist (HSA), Electronic Roll Mitigation (ERM), and Electronic Stability Control (ESC). These systems work together to enhance both vehicle stability and control in various driving conditions.

Two additional electronic brake control system options are Hill Descent Control (HDC) and Trailer Sway Control (TSC). Your vehicle may be equipped with one or both of these options.

Anti-Lock Brake System (ABS)

This system aids the driver in maintaining vehicle control under adverse braking conditions. The system controls hydraulic brake pressure to prevent wheel lock-up to help avoid skidding on slippery surfaces during braking.

Refer to “Anti-Lock Brake System” in “Starting and Operating” for further information.

WARNING!
The Anti-Lock Brake System (ABS) cannot prevent the natural laws of physics from acting on the vehicle, nor can it increase the traction afforded by prevailing road conditions. ABS cannot prevent collisions, including those resulting from excessive speed in turns, driving on very slippery surfaces, or hydroplaning. The capabilities of an ABS-equipped vehicle must never be exploited in a reckless or dangerous manner, which could jeopardize the user’s safety or the safety of others.

Traction Control System (TCS)

This system monitors the amount of wheel spin of each of the driven wheels. If wheel spin is detected, brake pressure is applied to the slipping wheel(s) and engine power is reduced to provide enhanced acceleration and stability. A feature of the TCS system functions similar to a limited slip differential and controls the wheel spin across a driven axle. If one wheel on a driven axle is spinning faster than the other, the system will apply the brake of the spinning wheel. This will allow more engine torque to be applied to the wheel that is not spinning.

This feature remains active even if TCS and ESC are in the “Partial Off” mode or the “Full Off” mode. Refer to “Electronic Stability Control (ESC)” in this section for further information.

Brake Assist System (BAS)

The BAS is designed to optimize the vehicle’s braking capability during emergency braking maneuvers. The system detects an emergency braking situation by sensing the rate and amount of brake application and then applies optimum pressure to the brakes. This can help reduce braking distances. The BAS complements the anti-lock brake system (ABS). Applying the brakes very quickly results in the best BAS assistance. To receive the benefit of the system, you must apply continuous braking pressure during the stopping sequence, (do not “pump” the brakes). Do not reduce brake pedal pressure unless braking is no longer desired. Once the brake pedal is released, the BAS is deactivated.

WARNING!
The Brake Assist System (BAS) cannot prevent the natural laws of physics from acting on the vehicle, nor can it increase the traction afforded by prevailing road conditions. BAS cannot prevent collisions, including those resulting from excessive speed in turns, driving on very slippery surfaces, or hydroplaning.

The capabilities of a BAS-equipped vehicle must never be exploited in a reckless or dangerous manner, which could jeopardize the user’s safety or the safety of others.

Electronic Roll Mitigation (ERM)

This system anticipates the potential for wheel lift by monitoring the driver’s steering wheel input and the speed of the vehicle. When ERM determines that the rate of change of the steering wheel angle and vehicle’s speed are sufficient to potentially cause wheel lift, it then applies the appropriate brake and may also reduce engine power to lessen the chance that wheel lift will occur. ERM will only intervene during very severe or evasive driving maneuvers. ERM can only reduce the chance of wheel lift occurring during severe or evasive driving maneuvers. It cannot prevent wheel lift due to other factors, such as road conditions, leaving the roadway, or striking objects or other vehicles.

NOTE: ERM is disabled anytime the ESC is in “Full Off” mode. Refer to Electronic Stability Control (ESC) for a complete explanation of the available ESC modes.

WARNING!
Many factors, such as vehicle loading, road conditions, and driving conditions, influence the chance that wheel lift or rollover may occur. Electronic Roll Mitigation (ERM) cannot prevent all wheel lift or rollovers, especially those that involve leaving the roadway or striking objects or other vehicles. The capabilities of an ERM-equipped vehicle must never be exploited in a reckless or dangerous manner, which could jeopardize the user’s safety or the safety of others.

Hill Start Assist (HSA)

The HSA system is designed to help the driver accelerate the vehicle from a complete stop while on an incline. If the driver releases the brake while stopped on an incline, HSA will continue to hold the brake pressure for a short period. If the driver does not apply the throttle before this time expires, the system will release brake pressure and the vehicle will roll down the hill as normal. The system will release brake pressure in proportion to amount of throttle applied.

The following conditions must be met in order for HSAto activate:

• The vehicle must be stopped.

• The vehicle must be on a 7% or greater incline.

• The gear selection must match vehicle uphill direction (i.e., vehicle facing uphill is in forward gear; vehicle backing uphill is in REVERSE gear).

• For vehicles equipped with an automatic transmission, the HSA will work in REVERSE gear and all forward gears. The system will not activate if the transmission is in PARK.

WARNING!
There may be situations where the Hill Start Assist (HSA) will not activate and slight rolling may occur, such as on minor hills (i.e., less than 7%), or with a loaded vehicle, or while pulling a trailer. HSA is not a substitute for active driving involvement. It is always the driver’s responsibility to be attentive to distance to other vehicles, people, and objects, and most importantly brake operation to ensure safe operation of the vehicle under all road conditions.

Failure to follow these warnings can result in a collision or serious personal injury.

Towing With HSA

HSA will provide assistance during acceleration on an incline while towing a trailer.

WARNING!
• If you use a trailer brake controller with your trailer, the trailer brakes may be activated and deactivated with the brake switch. If so, there may not be enough brake pressure to hold both the vehicle and the trailer on a hill when the brake pedal is released. In order to avoid rolling down an incline while resuming acceleration, manually activate the trailer brake or apply more vehicle brake pressure prior to releasing the brake pedal.

• Failure to follow these warnings can result in a collision or serious personal injury.

Disabling And Enabling HSA

This feature can be turned on or turned off. To change the current setting, proceed as follows:

For vehicles equipped with the Electronic Vehicle Information Center (EVIC), refer to “Hill Start Assist,” under Personal Settings (Customer Programmable Features),” under “Electronic Vehicle Information Center (EVIC)” in “Understanding Your Instrument Panel” for further information.

For vehicles not equipped with the EVIC, perform the following steps:

NOTE: You must complete Steps 1 through 8 within 90 seconds.

1. Center the steering wheel (front wheels pointing straight forward).

2. Shift the transmission into PARK 3. Apply the parking brake.

4. Start the engine.

5. Rotate the steering wheel one-half turn to the left.

6. Press the “ESC Off” button located in the lower switch bank below the climate control four times within twenty seconds. The “ESC Off Indicator Light” should turn on and turn off two times.

7. Rotate the steering wheel back to center and then an additional one-half turn to the right.

8. Turn the ignition switch to the OFF position and then back to the ON position. If the sequence was completed properly, the “ESC Off Indicator Light” will blink several times to confirm HSA is disabled.

9. Repeat these steps if you want to return this feature to its previous setting.

Hill Descent Control (HDC) – If Equipped

HDC is only intended for low speed off-road driving.

HDC maintains vehicle speed while descending hills in off-road driving conditions by applying the brakes when necessary.

When enabled, HDC senses the terrain and activates when the vehicle is descending a hill. HDC speed may be adjusted by the driver to suit the driving conditions. The speed corresponds to the transmission gear selected.

However, the driver can override HDC operation by applying the brake to slow the vehicle down below the HDC control speed. If more speed is desired during HDC control, the accelerator pedal will increase vehicle speed in the usual manner. When either the brake or the accelerator is released, HDC will control the vehicle at the original set speed.

NOTE: HDC is available on vehicles equipped with the MP1522 transfer case.

• The transfer case must be in 4WD LOW range to enable HDC.

• HDC is enabled only when the “Hill Descent Control Indicator Light” in the instrument cluster is on solid.

• HDC will NOT activate when the automatic transmission is in PARK.

• HDC will NOT activate on level ground.

• HDC will NOT activate at vehicle speeds above 30 mph (50 km/h).

The “Hill Descent” button is located in the lower switch bank below the climate control.

Hill Descent Button

Enabling HDC

1. Shift the transfer case into 4WD LOW range. Refer to “Four-Wheel Drive Operation” in “Starting and Operating” for further information.

2. Press the “Hill Descent” button. The “Hill Descent Control Indicator Light” in the instrument cluster will turn on solid.

NOTE: If the transfer case is not in 4WD LOW range, the “Hill Descent Control Indicator Light” will flash for five seconds and HDC will not be enabled.

Disabling HDC

1. Press the “Hill Descent” button or shift the transfer case out of 4WD LOW range. The “Hill Descent Control Indicator” light in the instrument cluster will turn off.

Electronic Stability Control (ESC)

This system enhances directional control and stability of the vehicle under various driving conditions. ESC corrects for oversteering or understeering of the vehicle by applying the brake of the appropriate wheel to assist in counteracting the oversteer or understeer condition. Engine power may also be reduced to help the vehicle maintain the desired path.

ESC uses sensors in the vehicle to determine the vehicle path intended by the driver and compares it to the actual path of the vehicle. When the actual path does not match the intended path, ESC applies the brake of the appropriate wheel to assist in counteracting the oversteer or understeer condition.

• Oversteer - when the vehicle is turning more than appropriate for the steering wheel position.

• Understeer - when the vehicle is turning less than appropriate for the steering wheel position.

The “ESC Activation/Malfunction Indicator Light” located in the instrument cluster will start to flash as soon as the tires lose traction and the ESC system becomes active. The “ESC Activation/Malfunction Indicator Light” also flashes when the TCS is active. If the “ESC Activation/Malfunction Indicator Light” begins to flash during acceleration, ease up on the accelerator and apply as little throttle as possible. Be sure to adapt your speed and driving to the prevailing road conditions.

WARNING!
The Electronic Stability Control (ESC) cannot prevent the natural laws of physics from acting on the vehicle, nor can it increase the traction afforded by prevailing road conditions. ESC cannot prevent collisions, including those resulting from excessive speed in turns, driving on very slippery surfaces, or hydroplaning. The capabilities of an ESC equipped vehicle must never be exploited in a reckless or dangerous manner which could jeopardize the user’s safety or the safety of others.

ESC Operating Modes

Depending upon model and mode of operation, the ESC system has up to three operating modes: “ESC On” “Partial Off,” and “Full Off.”

ESC On – Two-Wheel Drive Vehicles And Four-Wheel Drive Vehicles In 2WD And 4WD High Range

This is the normal operating mode for ESC when operating a two-wheel drive vehicle. It is also the normal mode for operating a four-wheel drive vehicle in 2WD or 4WD HIGH range. The ESC system will be in “ESC On” mode whenever the vehicle is started or the transfer case (if equipped) is shifted out of 4WD LOW range. This mode should be used for most driving situations. ESC should only be turned to “Partial Off” or “Full Off” for specific reasons as noted. Refer to “Partial Off” and to “Full Off” for additional information.

Partial Off – Two-Wheel Drive Vehicles And Four-Wheel Drive Vehicles In 2WD And 4WD High Range

The “Partial Off” mode is intended for driving in deep snow, sand, or gravel. This mode raises the threshold for TCS and ESC activation, which allows for more wheel spin than what ESC normally allows.

The “ESC Off” button is located in the lower switch bank below the climate control. To enter the “Partial Off” mode, momentarily press the “ESC Off” button and the ESC Activation/Malfunction Indicator Light” will illuminate.

To turn the ESC on again, momentarily press the ESC Off button and the ESC Activation/Malfunction Indicator Light” will turn off. This will restore the normal “ESC On” mode of operation.

NOTE: To improve the vehicle’s traction when driving with snow chains, or when starting off in deep snow, sand, or gravel, it may be desirable to switch to the “Partial Off” mode by momentarily pressing the “ESC Off” button. Once the situation requiring “Partial Off” mode is overcome, turn ESC back on by momentarily pressing the “ESC Off” button. This may be done while the vehicle is in motion.

Full Off – Four-Wheel Drive Vehicles In 4WD High And 4WD Low Range

The “Full Off” mode is intended for off-highway and off-road use when ESC stability features could inhibit vehicle maneuverability due to trail conditions.

The “ESC Off” button is located in the lower switch bank below the climate control panel. To enter “Full Off” mode, press and hold the “ESC Off” button for five seconds while the vehicle is stopped with the engine running. After five seconds, the “ESC Activation/ Malfunction Indicator Light” will illuminate and an “ESC OFF” message will appear in the odometer. Press and release the trip odometer button located on the instrument cluster to turn off this message.

In this mode, ESC and TCS are turned off (except for the “limited slip” feature described in the TCS section) until the vehicle reaches a speed of 40 mph (64 km/k). At speeds over 40 mph (64 km/k), the system automatically switches to “Partial Off” mode, described above. When the vehicle speed returns to less than 35 mph (56 km/h), the ESC system will return to “Full Off” mode. The “ESC Activation/Malfunction Indicator Light” is always illuminated when ESC is off. To turn ESC on again, momentarily press the “ESC Off” button. This will restore the normal “ESC On” mode of operation.

NOTE:
• “Full Off” is the only operating mode for ESC in 4WD LOW range. The ESC system will be in this mode whenever the vehicle is started in 4WD LOW range or the transfer case is shifted into 4WD LOW range.

• The “ESC OFF” message will display and a chime will sound when the shift lever is moved from any position to the PARK position and then moved out of the PARK position. This will occur even if the message was cleared previously.

WARNING!
With the ESC switched off, the enhanced vehicle stability offered by ESC is unavailable. In an emergency evasive maneuver, the ESC system will not engage to assist in maintaining stability. “Full Off” mode is only intended for off-highway or off-road use.

ESC Activation/Malfunction Indicator Light And ESC Off Indicator Light

The “ESC Activation/Malfunction Indicator Light” in the instrument cluster will come on when the ignition switch is turned to the ON position. It should go out with the engine running. If the “ESC Activation/Malfunction Indicator Light” comes on continuously with the engine running, a malfunction has been detected in the ESC system. If this light remains on after several ignition cycles, and the vehicle has been driven several miles (kilometers) at speeds greater than 30 mph (48 km/h), see your authorized dealer as soon as possible to have the problem diagnosed and corrected.

The “ESC Activation/Malfunction Indicator Light” (located in the instrument cluster) starts to flash as soon as the tires lose traction and the ESC system becomes active.

The “ESC Activation/Malfunction Indicator Light” also flashes when TCS is active. If the “ESC Activation/ Malfunction Indicator Light” begins to flash during acceleration, ease up on the accelerator and apply as little throttle as possible. Be sure to adapt your speed and driving to the prevailing road conditions.

NOTE:
• The “ESC Activation/Malfunction Indicator Light” and the “ESC OFF Indicator Light” come on momentarily each time the ignition switch is turned ON.

• The ESC system will make buzzing or clicking sounds when it is active. This is normal; the sounds will stop when ESC becomes inactive following the maneuver that caused the ESC activation.

The “ESC OFF Indicator Light” indicates the Electronic Stability Control (ESC) is off.

Anti-Lock Brake System

Tire Safety Information