Tire Pressure Monitoring System (TPMS) warns the driver of significant changes in pressure in any of the four tires and allows the driver to display individual tire pressures on the Driver Information Center (DIC) while the vehicle is in motion and its location.driven.
The TPMS uses the body control module (BCM), instrument panel cluster (IPC), DIC, radio frequency (RF) transmission pressure sensors and serial data circuits in each wheel/tire assembly to perform system functions.
The sensor enters stationary mode when the vehicle is stationary and the accelerometer inside the sensor is not activated.In this mode, the sensor samples tire pressure every 30 seconds and only sends rest mode transmissions when the air pressure changes.
As vehicle speed increases, centrifugal force activates the internal accelerometer, which puts the sensor into roll mode.In this mode, the sensor samples tire pressure every 30 seconds and sends a rolling mode transmission every 60 seconds.
The BCM takes the data contained in each sensor’s RF transmission and converts it into sensor presence, sensor mode, and tire pressure.The BCM then sends tire pressure and tire position data to the DIC via the serial data circuit, where it is displayed.
The sensor constantly compares its current pressure sample to its previous pressure sample and transmits it in remeasure mode whenever there is a 1.2 psi change in tire pressure.
When the TPMS detects a significant decrease or increase in tire pressure, a “CHECK TIRE PRESSURE” message will appear on the DIC and a low tire pressure indicator will appear on the IPC.Both the DIC message and the IPC indicator can be cleared by adjusting the tire pressure to the recommended pressure and driving the vehicle above 25 miles per hour (40 km/h) for at least two minutes.
The BCM is also capable of detecting faults within the TPMS.Any detected fault will cause the DIC to display the “SERVICE TIRE MONITOR” message and keep the TPMS IPC bulb lit for one minute each time the ignition is turned on until the fault is corrected.
When the TPMS detects a significant drop in tire pressure, a “CHECK TIRE PRESSURE” message will appear on the DIC and a low tire pressure indicator will appear on the instrument panel.
Messages and indicators can be cleared by adjusting the tires to the recommended pressure and driving the vehicle above 25 mph (40 km/h) for at least two minutes.If one or more tire pressure sensors or other system components have failed, or if all sensors were not successfully programmed.If the warning light is still on, there is a problem with the TPMS.Please refer to the appropriate manufacturer’s service information.
NOTE: Relearn the tire pressure sensor when the wheel is rotated or after the tire pressure sensor is replaced.When the TPMS detects a significant drop in tire pressure, a “CHECK TIRE PRESSURE” message will appear on the DIC and a low tire pressure indicator will appear on the instrument panel.
Messages and indicators can be cleared by adjusting the tires to the recommended pressure and driving the vehicle above 25 mph (40 km/h) for at least two minutes.
NOTE: Once TPMS learning mode is enabled, each sensor unique identification (ID) code can be learned into the BCM memory.After learning the sensor ID, the BCM will beep.This verifies that the sensor has sent an ID and that the BCM has received and learned it.
The BCM must learn the sensor IDs in the correct order to determine the correct sensor location.The first learned ID is assigned to the left front, the second to the right front, the third to the right rear, and the fourth to the left rear.
NOTE: Each transducer has an internal low frequency (LF) coil.When the tool is used in active mode, it produces low frequency transmissions that activate the sensor.The sensor responds to LF activation by transmitting in learning mode.When the BCM receives a learn mode transmission in TPMS learn mode, it will assign that sensor ID to a position on the vehicle relative to its learn order.
NOTE: The sensor function uses the pressure increase/decrease method.In quiescent mode, each sensor takes a pressure measurement sample every 30 seconds.If tire pressure increases or decreases by more than 1.2 psi from the last pressure measurement, another measurement will be taken immediately to verify the pressure change.If a pressure change does occur, the sensor transmits in learning mode.
When the BCM receives a learn mode transmission in TPMS learn mode, it will assign that sensor ID to a position on the vehicle relative to its learn order.
NOTE: Learning mode will cancel if ignition is cycled to OFF or any sensor that has not been learned for more than two minutes.If you cancel learning mode before learning the first sensor, the original sensor ID will be preserved.If learning mode is canceled for any reason after learning the first sensor, all IDs will be removed from the BCM memory and the DIC will display a dash for tire pressure if equipped.
If you do not use the scanning tool to initiate the relearn process, you may inadvertently learn spurious signals from other TPMS-equipped vehicles.If you hear any random horn chirps from the vehicle while performing the learning process, it is likely that the stray sensor has been learned and the process needs to be canceled and repeated.In these cases, it is strongly recommended to perform the TPMS learning procedure away from other vehicles.
In cases where activation of a particular sensor does not cause the horn to beep, it may be necessary to rotate the wheel valve stem to a different position because the sensor signal is blocked by another component.Before proceeding with the following steps, verify that no other sensor learning routines are in progress nearby; tire pressure is not being adjusted on another nearby TPMS-equipped vehicle; and the parking brake switch input parameters are functioning properly:
Turn on the ignition switch and turn off the engine.The DIC is accessed via the five-way control on the right side of the steering wheel.Scroll to the tire pressure screen and make sure the option to display tire pressure information is turned on.The information display on the DIC can be turned on and off through the Options menu;
Using the scan tool or DIC, select the tire pressure sensor to relearn.After this step is completed, a double horn chirp will sound, and the front left turn signal light will be on;
Starting with the left front tire, use one of the following methods to learn tire pressure: Method 1: Hold the TPMS tool’s antenna against the tire sidewall near the rim where the valve stem is, then press and release the activation button and wait for the horn to chirp.
Method 2: Increase/decrease tire pressure for 8 to 10 seconds and wait for the horn to chirp.Horn chirps may occur up to 30 seconds before or up to 30 seconds after reaching a pressure increase/decrease period of 8 to 10 seconds.
After the horn chirps, continue to repeat the process for the remaining three sensors in the following order: front right, rear right, and rear left;
After learning the LR sensor, a double-horn chirp will sound, indicating that all sensors have been learned;
NOTE: Tires should be removed from the wheel in accordance with the tire changer manufacturer’s instructions.Use the following information to avoid damage during removal/installation.
NOTE: The TPMS may issue an inaccurate low pressure warning if the vehicle tires are replaced with tires that do not have a Tire Performance Standard Specification (TPC Spec) number.Non-TPC sized tires may issue a low pressure warning above or below the appropriate warning level achieved by the TPC
Retrain the tire pressure sensor after the wheel is rotated or the tire pressure sensor is replaced.(See Reset Procedure.)
NOTE: Do not inject any tire fluid or aerosol tire sealant into the tire as this may cause the tire pressure sensor to malfunction.If any tire sealant is found when removing the tire, replace the sensor.Also remove any residual liquid sealant from the inside of the tire and wheel surfaces.
3. Remove the TORX screw from the tire pressure sensor and pull it straight off the tire pressure valve stem.(See Figure 1.)
1. Assemble tire pressure sensor to valve stem and install new TORX screw.Tire pressure valve and TORX screw are for single use only;
3. Using the tire valve stem installation tool, pull out the valve stem in a direction parallel to the valve hole on the rim;
5. Install the tire on the wheel.Install the tire/wheel assembly to the vehicle.and retrain the tire pressure sensor.(See Reset Procedure.)
The information in this column comes from the tire pressure monitoring system data in the domestic and imported automobile maintenance information software ProDemandR of Mitchell 1.Headquartered in Poway, California, Mitchell 1 has been providing the automotive industry with premium repair information solutions since 1918.For more information, visit www.mitchell1.com.To read archived TPMS articles, visit www.moderntiredealer.com.
Post time: Jan-08-2022