2022 Jeep Wrangler Auxiliary Driving Systems
AUXILIARY DRIVING SYSTEMS
BLIND-SPOT MONITORING (BSM) —IF EQUIPPED
The BSM system uses two radar sensors, located inside the taillights, to detect highway licensable vehicles (automobiles, trucks, motorcycles, etc.) that enter the blind spot zones from the rear/front/side of the vehicle.
- When the vehicle is started, the BSM Warning Light will momentarily illuminate in both outside rearview mirrors to let the driver know that the system is operational. The BSM system sensors operate when the vehicle is in any forward gear and enters standby mode when the vehicle is in PARK (P).
- The BSM detection zone covers approximately one lane width on both sides of the vehicle 12 ft
(3.8 m). The zone length starts at the outside rearview mirror and extends approximately 10 ft (3 m) beyond the rear fascia/bumper of the vehicle. The BSM system monitors the detection zones on both sides of the vehicle when the vehicle speed reaches approximately 6 mph (10 km/h) or higher and will alert the driver of vehicles in these areas.
NOTE
- The BSM system DOES NOT alert the driver about rapidly approaching vehicles that are outside the detection zones.
- The BSM system detection zone DOES NOT change if your vehicle is towing a trailer. Therefore, visually verify the adjacent lane is clear for both your vehicle and trailer before making a lane change. If the trailer or other object (i.e., bicycle, sports equipment) extends beyond the side of your vehicle, this may result in the BSM Warning Light remaining illuminated the entire time the vehicle is in a forward gear page 207.
- The Blind Spot Monitoring (BSM) system may experience dropouts (blinking on and off) of the side mirror warning indicator lamps when a motorcycle or any small object remains at the side of the vehicle for extended periods of time (more than a couple of seconds).
The BSM system can become blocked if snow, ice, mud, or other road contaminations accumulate on the rear fascia/bumper where the radar sensors are located. The system may also detect blockage if the vehicle is operated in areas with extremely low radar returns such as a desert or parallel to a large elevation drop. If the blockage is detected, a
“Blind Spot Temporarily Unavailable, Wipe Rear Corners” message will display in the cluster, both mirror lights will illuminate, and BSM and RCP alerts will not occur. This is a normal operation. The system will automatically recover and resume function when the condition clears. To minimize system blockage, do not block the area of the rear fascia/bumper where the radar sensors are located with foreign objects (bumper stickers, bicycle racks, etc.) and keep it clear of road contaminations.
BSM Radar Location (Left Side Shown)
The BSM system notifies the driver of objects in the detection zones by illuminating the BSM Warning Light located in the outside mirrors in addition to sounding an audible (chime) alert and reducing the radio volume page 287.
The BSM system monitors the detection zone from three different entry points (side, rear, front) while driving to see if an alert is necessary. The BSM system will issue an alert during these types of zone entries.
Entering From The Side
Vehicles that move into your adjacent lanes from either side of the vehicle.
Entering From The Rear
Vehicles that come up from behind your vehicle on either side and enter the rear detection zone with a relative speed of less than 30 mph (48 km/h).
Overtaking Traffic
If you pass another vehicle slowly with a relative speed of less than 15 mph (24 km/h) and the vehicle remains in the blind spot for approximately 1.5 seconds, the warning light will be illuminated. If the difference in speed between the two vehicles is greater than 15 mph (24 km/h), the warning light will not illuminate.
Overtaking/Passing
The BSM system is designed not to issue an alert on stationary objects such as guardrails, posts, walls, foliage, berms, etc. However, occasionally the system may alert on such objects. This is a normal operation and your vehicle does not require service. The BSM system will not alert you of objects that are traveling in the opposite direction of the vehicle in adjacent lanes page 431.
WARNING
The Blind Spot Monitoring system is only an aid to help detect objects in the blind spot zones. The BSM system is not designed to detect pedestrians, bicyclists, or animals. Even if your vehicle is equipped with the BSM system, always check your vehicle’s mirrors, glance over your shoulder, and use your turn signal before changing lanes. Failure to do so can result in serious injury or death.
Rear Cross Path (RCP)
RCP is intended to aid the driver when backing out of parking spaces where their vision of oncoming vehicles may be blocked. Proceed slowly and cautiously out of the parking space until the rear end of the vehicle is exposed. The RCP system will then have a clear view of the cross traffic and if an oncoming vehicle is detected, alert the driver.
RCP Detection Zones
RCP monitors the rear detection zones on both sides of the vehicle, for objects that are moving toward the side of the vehicle with a minimum speed of approximately 3 mph (5 km/h), to objects moving a maximum of approximately 20 mph (32 km/h), such as in parking lot situations. When RCP is on and the vehicle is in REVERSE, the driver is alerted using both the visual and audible alarms, including reducing the radio volume.
NOTE: In a parking lot situation, oncoming vehicles can be blocked by vehicles parked on either side. If the sensors are blocked by other structures or vehicles, the system will not be able to alert the driver.
WARNING
Rear Cross Path Detection (RCP) is not a backup aid system. It is intended to be used to help a driver detect an oncoming vehicle in a parking lot situation. Drivers must be careful when backing up, even when using RCP. Always check carefully behind your vehicle, look behind you, and be sure to check for pedestrians, animals, other vehicles, obstructions, and blind spots before backing up. Failure to do so can result in serious injury or death.
Blind Spot Modes
Blind Spot has three selectable modes of operation that are available in the Uconnect system.
Blind Spot Alert Lights Only
When operating in Blind Spot Alert mode, the BSM system will provide a visual alert in the appropriate side-view mirror based on a detected object. However, when the system is operating in Rear Cross Path (RCP) mode, the system will respond with both visual and audible alerts when a detected object is present. Whenever an audible alert is requested, the radio is muted.
Blind Spot Alert Lights/Chime
When operating in Blind Spot Alert Lights/Chime mode, the BSM system will provide a visual alert in the appropriate side-view mirror based on a detected object. If the turn signal is then activated, and it corresponds to an alert present on that side of the vehicle, an audible chime will also be sounded. Whenever a turn signal and detected object are present on the same side at the same time, both the visual and audible alerts will be issued. In addition to the audible alert, the radio (if on) will also be muted.
NOTE
Whenever an audible alert is requested by the BSM system, the radio is also muted. When the system is in RCP, the system shall respond with both visual and audible alerts when a detected object is present. Whenever an audible alert is requested, the radio is also muted. Turn/hazard signal status is ignored; the RCP state always requests the chime.
Blind Spot Alert Off
When the BSM system is turned off there will be no visual or audible alerts from either the BSM or RCP systems.
NOTE: The BSM system will store the current operating mode when the vehicle is shut off. Each time the vehicle is started the previously-stored mode will be recalled and used.
Door Removal
When either the front driver or passenger door is removed, the instrument cluster will display “Blind Spot Temporarily Unavailable” and the BSM system will disable. While the system will continue to indicate whatever blind spot mode it was previously in within the Uconnect system, no visual or audible alerts will be provided. As long as the doors are removed, the instrument cluster will provide the “Blind Spot Temporarily Unavailable” pop-up as a reminder that the system is disabled every time the ignition is cycled. Upon reinstallation of both doors, the system will resume functionality based on the personalized mode selected.
FORWARD COLLISION WARNING (FCW) WITH MITIGATION — IF EQUIPPED
The FCW with Mitigation system provides the driver with audible warnings, and visual warnings (within the instrument cluster display), and may apply a haptic warning in the form of a brake jerk, to warn the driver when it detects a potential frontal collision. The warnings are intended to provide the driver with enough time to react, avoid or mitigate the potential collision.
NOTE
- FCW monitors the information from the forward-looking sensors as well as Electronic Brake Controller (EBC), to calculate the probability of a forward collision. When the system determines that a forward collision is probable, the driver will be provided with audible and visual warnings as well as a possible haptic warning in the form of a brake jerk.
- If the driver does not take action based on these progressive warnings, then the system will provide a limited level of active braking to help slow the vehicle and mitigate the potential forward collision. If the driver reacts to the warnings by braking and the system determines that the driver intends to avoid the collision by braking but has not applied sufficient brake force, the system will compensate and provide additional brake force as required.
- If an FCW with a Mitigation event begins at a speed below 32 mph (52 km/h), the system may provide the maximum braking possible to mitigate the potential forward collision. If the Forward Collision Warning with Mitigation event stops the vehicle completely, the system will hold the vehicle at standstill for two seconds and then release the brakes.
FCW Message
When the system determines a collision with the vehicle in front of you is no longer probable, the warning message will be deactivated page 431.
NOTE
- The minimum speed for FCW activation is 3 mph (5 km/h).
- The FCW alerts may be triggered on objects other than vehicles such as guardrails or signposts based on the course prediction. This is expected and is a part of normal FCW activation and functionality.
- It is unsafe to test the FCW system. To prevent such misuse of the system, after four Active Braking events within a key cycle, the Active Braking portion of FCW will be deactivated until the next key cycle.
- The FCW system is intended for on-road use only. If the vehicle is taken off-road, the FCW system should be deactivated to prevent unnecessary warnings to the surroundings.
- FCW may not react to irrelevant objects such as overhead objects, ground reflections, objects not in the path of the vehicle, stationary objects that are far away, oncoming traffic, or leading vehicles with the same or higher rate of speed.
- FCW will be disabled like ACC, with the unavailable screens.
WARNING
Forward Collision Warning (FCW) is not intended to avoid a collision on its own, nor can FCW detect every type of potential collision. In rare situations, the system may react to surrounding objects such as tunnels, bridges, guardrails, etc. The driver has the responsibility to avoid a collision by controlling the vehicle via braking, steering, and acceleration. Unintended braking reactions can always be overridden by pressing down hard on the accelerator. Failure to follow this warning could lead to serious injury or death.
Turning FCW On Or Off
The FCW setting menu can be adjusted through the Uconnect Settings page 207.
- To turn the FCW system on, select “Only Warning” and “Warning and Braking” in the FCW menu.
- Select “OFF” in the FCW menu to turn the FCW system off.
NOTE
- When the FCW is “on”, this allows the system to warn the driver of a possible collision with the vehicle in front.
- When the FCW is “off”, this prevents the system from warning the driver of a possible collision with the vehicle in front. If the FCW is set to “off”, “FCW OFF” will be displayed in the instrument cluster display.
- When FCW status is set to “Only Warning”, this prevents the system from providing limited active braking, or additional brake support if the driver is not braking adequately in the event of a potential frontal collision.
- When FCW status is set to “Warning and Braking”, this allows the system to warn the driver of a possible collision with the vehicle in front using audible/visual warnings and it applies autonomous braking.
- The system will retain the last setting selected by the driver after the ignition shutdown.
FCW Braking Status And Sensitivity
The FCW Sensitivity and Active Braking status are programmable through the Uconnect system on page 207.
- Far
- When the sensitivity of FCW is set to the “Far” setting, this allows the system to warn the driver of a possible more distant collision with the vehicle in front using audible/visual warnings.
- More cautious drivers that do not mind
- frequent warnings may prefer this setting.
- NOTE: The “Far” setting may result in a greater number of FCW possible collision warnings experienced.
- Medium
- When the sensitivity of FCW is set to the “Medium” setting, this allows the system to warn the driver of a possible collision with the vehicle in front using audible/visual warnings.
- Near
- When the sensitivity of FCW is set to the “Near” setting, this allows the system to warn the driver of a possible closer collision with the vehicle in front using audible/visual warnings.
- This setting provides less reaction time than the “Far” and “Medium” settings, which allows for a more dynamic driving experience.
- More dynamic or aggressive drivers that want to avoid frequent warnings may prefer this setting.
NOTE: The “Near” setting may result in a lesser number of FCW possible collision warnings experienced.
FCW Limited Warning
If the instrument cluster displays “ACC/FCW Limited Functionality” or “ACC/FCW Limited Functionality Clean Front Windshield” momentarily, there may be a condition that limits FCW functionality. Although the vehicle is still drivable under normal conditions, the active braking may not be fully available. Once the condition that limited the system performance is no longer present, the system will return to its full performance state. If the problem persists, see an authorized dealer.
Service FCW Warning
If the system turns off, and the instrument cluster displays:
- ACC/FCW Unavailable Service Required
- Cruise/FCW Unavailable Service Required
This indicates there is an internal system fault. Although the vehicle is still drivable under normal conditions, have the system checked by an authorized dealer.
TIRE PRESSURE MONITORING SYSTEM (TPMS)
The Tire Pressure Monitoring System (TPMS) will warn the driver of a low tire pressure based on the vehicle’s recommended cold placard pressure.
NOTE: The alert warning on the cluster will stay on until the tire is inflated to the placard pressure.
The tire pressure will vary with temperature by approximately 1 psi (7 kPa) for every 12°F (6.5°C). This means that when the outside temperature decreases, the tire pressure will decrease. Tire pressure should always be set based on cold inflation tire pressure. This is defined as the tire pressure after the vehicle has not been driven for at least three hours, or driven less than 1 mile (1.6 km) after a three-hour period. The cold tire inflation pressure must not exceed the maximum inflation pressure molded into the tire sidewall. The tire pressure will also increase as the vehicle is driven. This is normal and there should be no adjustment for this increased pressure. See page 391 on how to properly inflate the vehicle’s tires. The TPMS will warn the driver of a low tire pressure if the tire pressure falls below the low-pressure warning limit for any reason, including low-temperature effects and natural pressure loss through the tire. The TPMS will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off until the tire pressure is at or above the recommended cold placard pressure. Once the low tire pressure warning (Tire Pressure Monitoring System Warning Light) illuminates, you must increase the tire pressure to the recommended cold placard pressure in order for the TPMS Warning Light to turn off.
NOTE: When filling warm tires, the tire pressure may need to be increased up to an additional 4 psi (28 kPa) above the recommended cold placard pressure in order to turn the TPMS Warning Light off.
- The system will automatically update and the TPMS Warning Light will turn off once the system receives the updated tire pressures. The vehicle may need to be driven for up to 20 minutes above 15 mph (24 km/h) in order for the TPMS to receive this information.
- For example, your vehicle may have a recommended cold (parked for more than three hours) placard pressure of 33 psi (227 kPa). If the ambient temperature is 68°F (20°C) and the measured tire pressure is 28 psi (193 kPa), a temperature drops to 20°F (-7°C) will decrease the tire pressure to approximately 24 psi (165 kPa). This tire pressure is low enough to turn on the TPMS Warning Light. Driving the vehicle may cause the tire pressure to rise to approximately 28 psi (193 kPa), but the TPMS Warning Light will still be on. In this situation, the TPMS Warning Light will turn off only after the tires are inflated to the vehicle’s recommended cold placard pressure value page 431.
- NOTE: When filling warm tires, the tire pressure may need to be increased up to an additional 4 psi (28 kPa) above the recommended cold placard pressure in order to turn the TPMS Warning Light off.
CAUTION
- The TPMS has been optimized for the original equipment tires and wheels. TPMS pressures and warnings have been established for the tire size equipped on your vehicle. Undesirable system operation or sensor damage may result when using replacement equipment that is not of the same size, type, and/or style. The TPMS sensor is not designed for use on aftermarket wheels and may contribute to poor overall system performance. Customers are encouraged to use Original Equipment Manufacturer (OEM) wheels to ensure TPMS feature operation.
- Using aftermarket tire sealants may cause the Tire Pressure Monitoring System (TPMS) sensor to become inoperable. After using an aftermarket tire sealant it is recommended that you take your vehicle to an authorized dealer to have your sensor function checked.
- After inspecting or adjusting the tire pressure always reinstall the valve stem cap. This will prevent moisture and dirt from entering the valve stem, which could damage the TPMS sensor.
NOTE
- The TPMS is not intended to replace normal tire care and maintenance or to provide a warning of a tire failure or condition.
- The TPMS should not be used as a tire pressure gauge while adjusting your tire pressure unless your vehicle is equipped with a Tire Fill Alert or Selectable Tire Fill Alert feature.
- Driving on a significantly underinflated tire causes the tire to overheat and can lead to tire failure. Underinflation also reduces fuel efficiency and tire tread life and may affect the vehicle’s handling and stopping ability.
- The TPMS is not a substitute for proper tire maintenance, and it is the driver’s responsibility to maintain correct tire pressure using an accurate tire pressure gauge, even if underinflation has not reached the level to trigger illumination of the TPMS Warning Light.
- Seasonal temperature changes will affect tire pressure, and the TPMS will monitor the actual tire pressure in the tire.
System Operation
The Tire Pressure Monitoring System (TPMS) uses wireless technology with wheel rim-mounted electronic sensors to monitor tire pressure levels. Sensors, mounted to each wheel as part of the valve stem, transmit tire pressure readings to the receiver module.
NOTE: It is particularly important for you to check the tire pressure in all of the tires on your vehicle monthly and to maintain the proper pressure. The TPMS consists of the following components:
- Receiver module
- Four Tire Pressure Monitoring System sensors
- Various Tire Pressure Monitoring System messages, which display in the instrument cluster
- Tire Pressure Monitoring Warning Light
TIRE PRESSURE MONITORING SYSTEM LOW-PRESSURE WARNINGS
The TPMS Warning Light will illuminate in the instrument cluster and a chime will sound when tire pressure is low in one or more of the four active road tires. In addition, the instrument cluster will display a “Tire Low” message for a minimum of five seconds, an “Inflate to XX” message, and a graphic showing the pressure values of each tire with the low tire pressure values in a different color.
Should this occur, you should stop as soon as possible and inflate the tires with low pressure (those in a different color in the instrument cluster graphic) to the vehicle’s recommended cold placard pressure value as shown in the “Inflate to XX” message. Once the system receives the updated tire pressures, the system will automatically update, the pressure values in the graphic display in the instrument cluster will return to their original color, and the TPMS Warning Light will turn off.
NOTE: When filling warm tires, the tire pressure may need to be increased up to an additional 4 psi (28 kPa) above the recommended cold placard pressure in order to turn the TPMS Warning Light off.
The vehicle may need to be driven for up to 20 minutes above 15 mph (24 km/h) in order for the TPMS to receive this information.
SERVICE TPMS WARNING
When a system fault is detected, the TPMS Warning Light will flash on and off for 75 seconds and then remain solid. The system fault will also sound like a chime. In addition, the instrument cluster will display a “SERVICE TIRE PRESSURE SYSTEM” message for a minimum of five seconds and then display dashes (–) in place of the pressure value to indicate which sensor is not being received.
If the ignition is cycled, this sequence will repeat, providing the system fault still exists. If the system fault no longer exists, the TPMS Warning Light will no longer flash, the “SERVICE TIRE PRESSURE SYSTEM” message will no longer display, and a pressure value will display in place of the dashes.
A system fault can occur due to any of the following:
- Jamming due to electronic devices or driving next to facilities emitting the same radio frequencies as the TPMS sensors
- Installing some form of aftermarket window tinting that affects radio wave signals
- Lots of snow or ice around the wheels or wheel housings
- Using tire chains on the vehicle
- Using wheels/tires not equipped with TPMS sensors
Vehicles With A Full-Size Matching Spare
- If your vehicle is equipped with a matching full-size spare wheel and tire assembly, it has a Tire Pressure Monitoring System sensor and can be monitored by the Tire Pressure Monitoring System (TPMS) when swapped with a low pressure road tire.
- In the event that the matching full-size spare tire is swapped with a low pressure road tire, the next ignition switch cycle will still show the TPMS Warning Light to be on, a chime to sound, an Inflate to XX message to appear in the instrument cluster, and the graphic display will still show the low tire pressure value in a different color.
- Driving the vehicle for up to 20 minutes above 15 mph (24 km/h) will turn off the TPMS Warning Light as long as none of the road tires are below the low-pressure warning threshold.
TPMS DEACTIVATION — IF EQUIPPED
- The TPMS can be deactivated if replacing all four-wheel and tire assemblies (road tires) with wheel and tire assemblies that do not have TPMS sensors, such as when installing winter wheel and tire assemblies on your vehicle.
- To deactivate the TPMS, first replace all four-wheel and tire assemblies (road tires) with tires not equipped with Tire Pressure Monitoring System sensors. Then, drive the vehicle for 20 minutes above 15 mph (24 km/h). The TPMS will chime, and the TPMS Warning Light will flash on and off for 75 seconds and then remain on. The instrument cluster will display the “SERVICE TIRE PRESSURE SYSTEM” message and then display dashes (–) in place of the pressure values.
- Beginning with the next ignition cycle, the TPMS will no longer chime or display the “SERVICE TIRE PRESSURE SYSTEM” message in the instrument cluster but dashes (–) will remain in a place of the pressure values.
- To reactivate the TPMS, replace all four-wheel and tire assemblies (road tires) with tires equipped with TPMS sensors. Then, drive the vehicle for up to 20 minutes above 15 mph (24 km/h). The TPMS
- will chime, and the TPMS Warning Light will flash on and off for 75 seconds and then turn off. The instrument cluster will display the “SERVICE TIRE PRESSURE SYSTEM” message and then display pressure values in place of the dashes. On the next ignition cycle, the “SERVICE TIRE PRESSURE SYSTEM” message will no longer be displayed as long as no system fault exists.
TIRE FILL ALERT
- This feature notifies the user when the placard tire pressure is attained while inflating or deflating the tire.
- The customer may choose to disable or enable the Tire Fill Alert feature in the customer settings menu of the Uconnect system.
NOTE
- Only one tire can be filled at a time when using the Tire Fill Alert system.
- The Tire Fill Alert feature cannot be entered if an existing TPMS fault is set to “active” or if the system is in deactivation mode (if equipped).
The system will be activated when the system detects an increase in tire pressure while filling the tire. The ignition must be in the ON/RUN mode with the transmission in PARK for vehicles equipped with an automatic transmission. For vehicles equipped with a manual transmission, the parking brake must be applied.
NOTE
It is not required to have the engine running to enter Tire Fill Alert mode. The hazard lamps will come on to confirm the vehicle is in Tire Fill Alert mode. If the hazard lamps do not come on while inflating the tire, the Tire Pressure Monitoring System sensor may be in an inoperative position, preventing the TPMS sensor signal from being received. In this case, the vehicle may need to be moved slightly forward or backward.
When Tire Fill Alert mode is entered, the tire pressure display screen will be displayed in the instrument cluster.
Operation
- The horn will chirp once to let the user know when to stop filling the tire and when it reaches recommended pressure.
- The horn will chirp three times if the tire is over-filled and will continue to chirp every five seconds if the user continues to inflate the tire.
- The horn will chirp once again when enough air is let out to reach the proper inflation level.
- The horn will also chirp three times if the tire is then underinflated and will continue to chirp every five seconds if the user continues to deflate the tire.
NOTE: The Tire Fill Alert feature is set to “Disabled” every time the ignition is turned to “OFF”. To re-enable the Tire Fill Alert feature at the next ignition “RUN” state, the customer must re-enable the feature through the use of the customer settings in the radio.
SELECTABLE TIRE FILL ALERT (STFA) —IF EQUIPPED
The STFA system is an optional feature that is included as part of the normal Tire Fill Alert system. The system is designed to allow you to select a pressure to inflate or deflate the vehicle’s front and rear axle tires to, and to provide feedback while inflating or deflating the vehicle’s tires.
NOTE
To use the STFA feature, the Tire Fill Alert feature must be enabled through the use of the customer settings in the radio. In the Selectable Tire Fill Alert application, which is located in the apps menu of the Uconnect system, you will be able to select a pressure setting for both the front and rear axle tire pressures by scrolling through a pressure range from XX to 15 psi in 1 psi increments for each axle set. XX = the vehicle’s cold placard pressure values for the front and rear axles as shown on the vehicle placard pressure label. You may also store pressure values chosen for each axle in the Uconnect system application as preset pressure values. Up to two sets of preset pressure values can be stored in the Uconnect system for the front and rear axle. Once you select the tire pressures for the front and rear axles that you want to inflate or deflate too, you can begin inflating or deflating one tire at a time.
NOTE
- The STFA system will only support inflating or deflating one tire at a time.
- The system will be activated when the TPMS receiver module detects a change in tire pressure. The ignition must be in the ON/RUN mode, with the transmission in PARK in vehicles with an automatic transmission, and in NEUTRAL with the parking brake engaged in vehicles with a manual transmission. The hazard lamps will come on to confirm the vehicle is in Tire Fill Alert mode.
- When Tire Fill Alert mode is entered, the tire pressure screen will be displayed in the instrument cluster. If the hazard lamps do not come on while inflating or deflating the tire, the Tire Pressure Monitoring System sensor may be in an inoperative position, preventing the TPMS sensor signal from being received. In this case, the vehicle may need to be moved slightly forward or backward.
Horn chirps will indicate STFA status as tires are inflated/deflated. The horn will chirp under the following STFA states:
- The horn will chirp once when the selected pressure is reached to let you know when to stop inflating or deflating the tire.
- The horn will chirp three times if the tire is over-inflated or over-deflated.
- The horn will chirp once again when enough air is added or removed to reach the proper selected pressure level.