DESCRIPTION & OPERATION
Note. When the wheels have been rotated, or a tire pressure sensor has been replaced, retrain tire pressure sensors. See RESET PROCEDURES .
TIRE PRESSURE MONITOR (TPM) SYSTEM
The tire pressure monitor (TPM) system uses the body control module (BCM), Instrument Panel Cluster (IPC), 4 RF transmitting pressure sensors and the serial data circuit to perform the TPM learn mode functions. The sensor learn procedure must be performed after every tire rotation, BCM replacement, or sensor replacement. Once the TPM learn mode has been enabled, each of the sensor unique identification (ID) codes can be learned into the BCM memory. When a sensor ID has been learned, the BCM sounds a horn chirp. This verifies the sensor has transmitted it ID and the BCM has received and learned it. The BCM must learn the sensor IDs in the proper order to determine correct sensor location. The first learned ID is assigned to the left front, the second to right front, the third to right rear and the fourth to left rear.
Sensor Functions Using Pressure Increase/Decrease Method Each sensor takes a pressure measurement sample once every 30 seconds while in stationary mode. If the tire pressure increases, or decreases by more than 8.3 kPa (1.2 psi) from the last pressure measurement, another measurement will occur immediately to verify the change in pressure. If a pressure change has indeed occurred, the sensor transmits in learn mode. When the BCM receives a learn mode transmission while in TPM learn mode, it will assign that sensor ID to the location on the vehicle relative to the order in which it was learned.
Learn Mode Cancellation: The learn mode will cancel if the ignition is cycled to OFF or if more than 2 minutes has elapsed for any sensor that has not been learned. If the learn mode is cancelled before the first sensor is learned, the original sensor IDs will be maintained. If the learn mode is canceled for any reason after the first sensor is learned, all IDs are erased from the BCM memory and if equipped, the DIC will display dashes for tire pressures.
The BCM has the ability to detect malfunctions within the TPM system. Any malfunction detected will cause the DIC to display the SERVICE TIRE MONITOR message and flash the TPM IPC bulb for 1 minute before illuminating it continuously each time the ignition is turned ON until the malfunction is corrected.
TIRE PRESSURE MONITOR WARNING INDICATORS
The tire pressure monitor indicator icon on the IPC will flash for 1 minute and then remain illuminated and the DIC will display the "SERVICE TIRE MONITOR SYSTEM" message if one or more of the tire pressure sensors or other system components has malfunctioned or if all of the sensors have not been programmed successfully. If warning indicators are still on, there is a problem in the TPM system. See appropriate manufacturer service information.
RESET PROCEDURES
Note. When the wheels have been rotated, or a tire pressure sensor has been replaced, retrain tire pressure sensors.
When the TPM system detects a significant loss or gain of tire pressure, the CHECK TIRE PRESSURE message is displayed on the DIC and the low tire pressure indicator is displayed on the IPC. Both the DIC message and IPC indicator can be cleared by adjusting the tire pressure to the recommended kPa/psi and driving the vehicle above 25 mph (40km/h) for at least 2 minutes.
TIRE PRESSURE SENSOR RELEARN
| WARNING | If not utilizing a scan tool to initiate the relearn procedure, stray signals from other TPM equipped vehicles just driving by can be inadvertently learned. If any random horn chirps are heard from the vehicle while performing the learn procedure, most likely a stray sensor has been learned and the procedure will need to be cancelled and repeated. Under these circumstances, performing the TPM Learn Procedure away from other vehicles would be highly recommended. In the event a particular sensor activation does not cause the horn to chirp, it may be necessary to rotate the wheel valve stem to a different position due to the sensor signal is being blocked by another component. Before proceeding with the steps below, verify the following: No other sensor learn procedure is being performed simultaneously within close proximity. Tire pressures are not being adjusted on another TPM equipped vehicle within close proximity. Park Brake Switch input parameters are functioning correctly. |
- Apply the parking brake (Manual Transmission only).
- Turn ON the ignition, with the engine OFF.
- Using a scan tool or the DIC select Tire Pressure Sensor Relearn. A double horn chirp will sound and the left front turn signal will be illuminated.
- Starting with the left front tire, learn the tire pressure using one of the following methods: Method 1: Hold the antenna of the TPM sensor activation tool against the tire sidewall close to the wheel rim at the valve stem location then press and release the activate button and wait for a horn chirp. Method 2: Increase/decrease the tire pressure for 8-10 seconds then wait for a horn chirp. The horn chirp may occur before or up to 30 seconds after the 8-10 second pressure increase/decrease time period has been reached.
- After the horn chirp has sounded, repeat procedure for the remaining 3 sensors in the following order: Right front, Right rear, Left rear.
- After the LR sensor has been learned, a double horn chirp will sound indicating all sensors have been learned.
- Turn OFF the ignition to exit the learn mode.
- After the learn mode has been exited, adjust all tires to the recommended pressures.
DISMOUNTING/MOUNTING PROCEDURES
| CAUTION | The tire should be dismounted from the wheel using the tire changer manufacturer's instructions. Use the following information to avoid damage during the dismounting/mounting procedures. |
Note. If vehicle's tires are replaced with those not having a TPC Spec number, the TPM system may give an inaccurate low pressure warning. Non-TPC Spec tires may give a low pressure warning that is higher or lower than the proper warning level achieved by TPC Spec numbered tires.
Note. When the wheels have been rotated, or a tire pressure sensor has been replaced, retrain tire pressure sensor. See RESET PROCEDURES .
TIRE PRESSURE SENSOR
| CAUTION | DO NOT inject any tire liquid or aerosol tire sealant into tires, as this may cause a malfunction of the tire pressure sensors. If any tire sealant is noted upon tire dismounting, replace the sensor. Also remove all residual liquid sealant from the inside of the tire and wheel surfaces. |
Removal
- Raise vehicle on a suitable support. Remove tire/wheel assembly from vehicle.
- Dismount tire from wheel following tire changer manufacturer's instructions.
- Remove the TORX screw (1) from the tire pressure sensor (2) and pull it straight off the tire pressure valve stem (3). (Scheme 6)
- Remove the tire pressure valve stem by pulling it through the rim.
Scheme 6
Installation
Note. When servicing the tire pressure sensor always use a new tire pressure monitor (TPM) and a new TORX screw during installation.
- Assemble the tire pressure sensor (2) to the valve stem and install the NEW TORX screw (3). Tire Pressure Monitor (TPM) valves and TORX screws are one-time use only.
- Apply tire soap to the rubber portion of the valve stem (1).
- Using a tire valve stem mounting tool, pull the valve stem through in a direction parallel to the valve hole on the rim.
- Mount the tire to the rim.
- Install tire on wheel. Install tire/wheel assembly on vehicle. Retrain tire pressure sensor. See «RESET PROCEDURES»(/cadillac/srx/ii-2009-2012/remont/reset-procedures/#tire-pressure-monitor-systems__reset-procedures) .
TORQUE SPECIFICATIONS
| Component | Ft. Lbs. (N.m) |
|---|---|
| Wheel Nut | 110 (150) |
| INCH Lbs. (N.m) | |
| Tire Pressure Sensor Torx Screw | 13 (1.5) |
TORQUE SPECIFICATIONS
See also:
• RESET PROCEDURES