Description | Base system | Premium system | Sensors |
Operation | Diagnostics & testing | Threshhold pressures | Sensor removal |
The Tire Pressure Monitoring (TPM) system monitors air pressure in the four road tires, or if the vehicle original equipment includes a full size matching spare, then all five tires. Pressure in the spare tire is not monitored with a compact spare or a "non-matching spare".
There are two tire pressure monitoring systems available for the 2011 Grand Cherokee, a base system and a premium system. The Base TPM system consists of tire pressure monitoring sensors attached to each road wheel (and spare if equipped with a sensor) valve stem, a central receiver module (Wireless Ignition Node (WIN)), and an indicator lamp. The valve stem used on this system is redesigned to look similar to a standard valve stem. The Premium TPM system consists of tire pressure monitoring sensors attached to each road wheel (and spare if equipped with a sensor) valve stem (similar to the base system valve stem, and a Tire Pressure Monitoring (TPM) module located behind the left rear wheel splash shield mounted to weld studs over the fuel inlet pipe bracket. Actual pressures are displayed for each of the four tires. The display is incorporated into the instrument cluster.
The tire pressure monitoring (TPM) system is designed to operate without loss of function for all OEM tire construction for this vehicle. Sensors, mounted to each road wheel (and spare if equipped with a sensor) as part of the valve stem, transmit an RF signal indicating their individual pressure to the Wireless Ignition Node (WIN). These transmissions occur approximately once every minute at speeds over 15 mph (24 km/h). If the TPM system detects that the tire pressure in any road tire is going low, beyond the Low Pressure (lamp) ON threshold (see placard table below), the TPM system will continuously illuminate an indicator lamp. If a system fault is detected, the indicator lamp will flash on/off for 75 seconds, then remain on solid. If the WIN module detects a warning or fault condition at ignition key "ON" it will wait ten seconds +/- 10 % before sending the first request to illuminate the indicator lamp. This will assure that the display module has concluded its bulb check period. The display module will request a chime once per ignition cycle for each "warning" or "fault" condition detected. A "warning" or "fault" condition will remain enabled until the problem causing the condition is corrected and removed/reset. The WIN module will store all warning and fault conditions, placard pressure values and low-pressure threshold values (lamp ON and OFF) in memory that can be accessed through diagnostic communication. If new sensors are introduced to the vehicle, the data stored for the sensor being replaced will be deleted. The WIN module will store all wheel sensor ID's and locations and faults in memory that can be accessed through diagnostic communication, and all other data values transmitted from each active wheel sensor. The WIN module shall continuously monitor for the receipt of tire pressure RF message transmissions from the wheel sensors during both the ignition key "ON" and key "OFF" cycles. The wheel sensor ID's and the location of each sensor (e.g. Tire 1, Tire 2 etc.) are learned by the WIN during the initial Manufacturing Plant Process, or during a service procedure, as required. The TPM System will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off the indicator lamp until the tire pressure is at or above the Low Pressure (lamp) OFF threshold (see placard table below). The system will automatically update and the TPM indicator lamp will extinguish once the updated tire pressures have been received. NOTE: A new sensor ID can also be programmed directly into the WIN module by using a RKE-TPM Analyzer in conjunction with a Scan Tool. Once the new sensor ID has been programmed, the vehicle will need to be driven above 15 mph until the fault is no longer active (lamp extinguishes) and display is updated (for up to 20 minutes). The WIN automatically learns and stores the sensor IDs while driving 'within 20 minutes continuously above 15 mph (24 km/h)' after a sensor has been replaced. The learning sequence will initiate when the vehicle has been stopped for more than 20 minutes. Tire pressure will vary with temperature by about 1 psi (6.9 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 (placard pressure). This is defined as the tire pressure after a vehicle has not been driven for more than 3 hours (and in outside ambient temperature). The tire pressure will also increase as the vehicle is driven; this is normal and there should be no adjustment for this increased pressure. For a system fault, the system will return to normal once the WIN receives a valid transmission from that sensor location. The recommended "Placard Pressure", "Low-pressure Threshold" (Low Pressure ON) and 'Hysteresis Pressure' values for the tires installed on the vehicle, are learned by the WIN module configuration during the initial Manufacturing Plant Process, or during a service procedure, as required. To determine the pressure thresholds for a vehicle, refer to the Tire Inflation Pressure (Placard) Label, and then apply the placard pressure to the following table. The Low Pressure OFF Threshold is defined as the Low Pressure ON Threshold plus the Hysteresis Pressure value.
The Tire Pressure Monitoring (TPM) system is designed to operate without loss of function for all OEM tire construction for this vehicle. Sensors, mounted to each road wheel (and spare if equipped with a sensor) as part of the valve stem, transmit an RF signal indicating their individual pressure to a receiver located in the Tire Pressure Monitoring (TPM) module. These transmissions occur approximately once every minute at speeds over 15 mph (24 km/h). If the TPM module detects that the tire pressure in any road tire is going low, beyond the Low Pressure (lamp) ON threshold (see placard table below), a chime will sound and the indicator lamp will turn on. In addition to the chime and lamp, a graphic display of the pressure value(s) and position of the low tire(s) will flash in the Electronic Vehicle Information Center (EVIC). Once pressure in the suspect tire(s) raises above the Low Pressure (lamp) OFF Threshold (see placard table below), and the TPM module receives a valid transmission from the sensor the lamp will go out. If a system fault is detected due to a missing sensor signal, in addition to a chime and a indicator lamp flashing, a "Check TPM System" text message will be displayed in the instrument cluster, and the tire pressure graphic display will display "- -" in place of the pressure value. After the flash sequence the TPM indicator lamp will remain illuminated. The system will return to normal once the TPM module receives a valid transmission from that sensor location. If a system fault is detected, the indicator lamp will flash on/off for 75 seconds and then remain on solid. If the TPM module detects a warning or fault condition at ignition key "ON" it will wait approximately ten seconds before sending the first request to illuminate the indicator lamp. This will assure that the display module has concluded its bulb check period. The display module will request a chime once per ignition cycle when a "warning" or "fault" condition is detected. A "warning" or "fault" condition will remain enabled until the problem causing the condition is corrected and reset. NOTE: A new sensor ID can also be programmed directly into the TPM module by using a RKE-TPM Analyzer in conjunction with a Scan Tool. Once the new sensor ID has been programmed, the vehicle will need to be driven above 15 mph until the fault is no longer active (lamp extinguishes) and display is updated (for up to 20 minutes). The TPM module shall continuously monitor for the receipt of tire pressure RF message transmissions from the wheel sensors during the ignition key "ON" cycle. The wheel sensor ID's and the location of each sensor (e.g. Tire 1, Tire 2 etc.) are learned by the TPM module using signal strength and direction of wheel rotation as received by the TPM module from each of the sensors, and updates the graphic display when necessary or during a service procedure, as required. The TPM System will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off the indicator lamp until the tire pressure is at or above the Low Pressure (lamp) OFF threshold (see placard table below). The system will automatically update and the TPM indicator lamp will turn off once the updated tire pressures have been received. Tire pressure will vary with temperature by about 1 psi (6.9 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 (placard pressure). This is defined as the tire pressure after a vehicle has not been driven for more than 3 hours (and in outside ambient temperature). The tire pressure will also increase as the vehicle is driven? this is normal and there should be no adjustment for this increased pressure. For a system fault, the system will return to normal once the TPM module receives a valid transmission from that sensor location. The recommended "Placard Pressure", "Low-pressure Threshold" (Low Pressure ON) and 'Hysteresis Pressure' values for the tires installed on the vehicle, are learned by the TPM module configuration during the initial Manufacturing Plant Process, or during a service procedure, as required. To determine the pressure thresholds for a vehicle, refer to the Tire Inflation Pressure (Placard) Label, and then apply the placard pressure to the following table. The Low Pressure OFF Threshold is defined as the Low Pressure ON Threshold plus the Hysteresis Pressure value.
NOTE: This vehicle uses the 433 MHz TPM sensor. Although 315 MHz and 433 MHz sensors are identical in size and shape, they are not interchangeable. Always make sure the correct sensor is being used. A RKE-TPM Analyzer can be used to determine the sensor's frequency without having to dismount the tire. The TPM sensors are designed for original style factory wheels. It is not recommended to install a tire pressure sensor in an aftermarket wheel. (This could cause sealing and system performance issues.) The serviceable components of the tire pressure sensor are:
CAUTION: 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 Tire Pressure Monitoring Sensor. CAUTION: Tire pressure sensor valve stem caps and cores are specially designed for the sensors. Due to risk of corrosion, do not use a standard valve stem cap or core in a tire pressure sensor in place of the original equipment style sensor cap and core. CAUTION: Any time a sensor is to be reinstalled in a wheel, a new valve stem assembly must be installed to ensure air tight sealing. NOTE: TPM thresholds have been established for the original tire size equipped on the vehicle. Use original size tires only to maintain system accuracy. CAUTION: The use of tire sealants is not recommended for vehicles equipped with the Tire Pressure Monitoring system. Tire sealants may clog tire pressure sensors. The battery operated tire pressure sensor is both a transmitter and a receiver. The TPM sensor can be forced to transmit if using a special tool such as a TPM-RKE Analyzer. The TPM-RKE Analyzer has the ability to change the sensor mode and to diagnose a faulty TPM sensor. Using a TPM-RKE Analyzer can take up to a minute to force a transmission from a sensor. Each sensor's (transmitter) broadcast is uniquely coded so that the module can monitor the state of each of the sensors on the four rotating road wheels. The module can automatically learn and store the sensor's ID while driving "within 10 minutes continuously above 15 m.p.h. (24 Km/h)" after a sensor has been replaced. The vehicle must be stationary for more then 20 minutes in order to initiate the learning sequence. The sensor IDs can also be programmed using the TPM-RKE Analyzer Tool. Scan each TPM sensor at each road wheel, and store each Sensor ID in the correct location. (LEFT FRONT, LEFT REAR, RIGHT FRONT, and RIGHT REAR) Connect the TPM-RKE Analyzer Tool to the Scan Tool. Then follow the programming steps outlined in the diagnostic Scan Tool for "Program Tire Pressure Sensor ID w/ TPM Tool" .
When diagnosing a tire pressure issue, first check the Tire Pressure Monitoring (TPM) indicator lamp in the instrument cluster during ignition key ON. From the OFF position, turn the key to ON and check the TPM indicator lamp to observe one of the following:
NOTE: Tire pressure may increase from 2 to 6 psi (14 to 41 kPa) during normal driving conditions. Do NOT reduce this normal pressure build up. NOTE: Tire pressure will vary with temperature by about 1 psi (6.9 kPa) for every 12°F (6.5°C). This means that when the outside temperature decreases, the tire pressure will also decrease. Tire pressure should always be set based on cold inflation tire pressure. Check air pressure as necessary in all tires using a known accurate air gauge and adjust to the specification listed on the Tire Inflation Pressure Label (Placard) provided with the vehicle (usually applied to the driver side B-pillar). After adjusting air pressure in a tire on the vehicle, allow approximately two minutes for the message or indicator lamp to go out. If air pressure in any tire is low, inspect all the tires for leaks. A water 'dunk tank' or other water test may be used to check for a leak around the sensor as long as any water at the valve core is removed once the procedure is completed. The water can be easily expelled from the core area by pushing in on the core for several seconds, allowing escaping air to drive out any moisture. Reinflate the tire as necessary. Always make sure the original (special) valve stem cap is securely installed to keep moisture out of the sensor. If the indicator lamp is still ON continuously, refer to the appropriate diagnostic information.
After an ignition key ON, if a system fault is detected, a chime will sound, and the TPM indicator (telltale) lamp will flash for 75 seconds, then remain on solid. A system fault can occur by many scenarios, including the following:
2. Remove tire and wheel assembly CAUTION: The cap used on this valve stem contains an O-ring seal to prevent contamination and moisture from entering the valve stem. Do not substitute a regular valve stem cap in its place. 3. Dismount tire from wheel following tire changer manufacturers instructions while paying special attention to the following to avoid damaging the pressure sensor: a. When breaking the tire bead loose from the wheel rim, avoid using the Bead Breaker in the area of the sensor (1). That includes both outer and inner beads of the tire. b. When preparing to dismount the tire from the wheel, carefully insert the mounting/dismounting tool 280° from the valve stem ± 10°, then proceed to dismount the tire from the wheel. Use this process on both outer and inner tire beads.
5. Remove the valve stem (2) from the wheel (4).
NOTE: If replacing tire pressure sensor, a new valve stem will be pre-mounted to the sensor as an assembly. Verify that the sensor is positioned properly before seating the valve stem. If replacing a valve stem only (using the existing tire pressure sensor), the new valve stem will include a new tire pressure sensor mounting screw. Always use a new mounting screw when attaching a sensor to a valve stem. CAUTION: Any time a sensor is to be reinstalled in a wheel, a new valve stem assembly must be installed to ensure air tight sealing. 1. Wipe area clean around sensor/valve stem mounting hole in wheel (4). Make sure surface of wheel is not damaged. NOTE: A new valve stem is pre-lubricated for proper installation with a standard tool. NOTE: If replacing tire pressure sensor, a new valve stem will be pre-mounted to the sensor as an assembly. Verify that the sensor is positioned properly before seating the valve stem. 2. Insert valve stem (2) through wheel (4) and pull through to seat with standard valve stem installation tool. 3. If replacing the valve stem (2) only (using the existing tire pressure sensor), verify that the flat sides of the brass extension on the bottom of the valve stem (2) are at a 90 degree angle with the wheel. Position the pressure sensor (1) over the brass extension, install the retainer screw (4) and tighten to 1.4 N·m (12 in. lbs.). 4. Mount tire on wheel following tire changer manufacturers instructions, paying special attention to the following to avoid damaging tire pressure sensor: a. Rotating Wheel Tire Changers - Once the wheel is mounted to the changer, position the sensor valve stem (2) approximately 280° from the head of the changer (located at 1) in a clockwise direction before rotating the wheel (also in a clockwise direction) to mount the tire. Use this procedure on both the outer and inner tire beads.
6. Install tire and wheel assembly on the vehicle. 7. Remove the support and lower the vehicle. 8. Perform one of the following to make the system learn the new sensor ID: a. Use the TPM-RKE Analyzer, 9936, with the Scan Tool to program the WIN with the tire pressure sensor ID. This is part of the TPM Diagnostic Verification Test. b. Once the vehicle has remained stationary for more than 20 minutes, drive vehicle for a minimum of 10 minutes while maintaining a continuous speed above 15 mph (24 km/h). During this time, the system will learn the new sensor ID. This is part of the TPM Diagnostic Verification Test. NOTE: If a sensor cannot be trained, refer to appropriate diagnostic information in the factory service manual. |