DESCRIPTION & OPERATION
The tire pressure monitor system warns the driver when a significant loss of tire pressure occurs in any of the equipped tires. It allows the driver to display the individual tire pressures and their locations on the driver information center. When the vehicle is stationary, the sensors internal shock sensor is inactive which puts the sensors into a stationary state. As vehicle speed increases, the shock sensor pulses every wheel rotation, which puts the sensor into rolling mode. The remote-control door lock receiver receives and then sends the tire pressure and temperature data to the body control module (BCM). The BCM translates the data contained in the tire pressure sensor radio frequency (RF) transmissions into sensor presence, sensor mode and tire pressure. Once vehicle speed is greater than 40 km/h (25 mph), the sensors begin to transmit once a minute keeping the pressure data up to date. Each sensor has its own unique identification (ID) code which it transmits as part of each RF message and must be learned into the BCM memory. Once all four IDs have been learned and vehicle speed is greater than 40 km/h (25 mph), the BCM continuously compares IDs and pressure data in the received transmissions to the learned ID's and pressures to determine if all four sensors are present and if one or more tires are low. If the BCM detects a low tire pressure condition, or a malfunction in the system, it will send a serial data message to the instrument cluster requesting the appropriate tire pressure monitor indicator illumination and also to display the appropriate data message on the driver information center, if equipped.
The sensors continuously compare their last pressure sample to their current pressure sample and will transmit in Alert mode if a 1.2 psi change in tire pressure has been detected in either a stationary or rolling state. When the tire pressure system detects a significant loss, or gain of tire pressure, the tire pressure monitor indicator icon is continuously illuminated on the instrument cluster and if equipped, a check tire pressure type message is displayed on the driver information center. Both the indicator icon and driver information center message can be cleared by adjusting the tire pressures to the recommended level.
If power is disconnected from the BCM or if the vehicle battery is disconnected each tire pressure sensor ID is retained but all of the tire pressure information is lost. Under these circumstances the BCM cannot assume that the tire pressures were maintained over an unknown period of time. Cars equipped with the driver information center will display dashes and the scan tool will indicate a default tire pressure value of 32 psi for each tire. To reactivate the sensors, the vehicle must be driven above 40 km/h (25 MPH) for at least two minutes. When the sensors are activated, the driver information center displays the current tire pressures. The EL-52545 tire pressure monitor sensor and RF diagnostic tool may also be used to activate the sensors as well.
TPMS SENSOR LEARN
Tire Pressure Sensor Learn with EL-52545 (Preferred)
The EL-52545 allows the tire pressure sensors to be learned without transmitting RF data between the tire pressure sensors and the vehicle. When using the EL-52545 each tire pressure sensor ID is learned to the EL-52545 and stored internally. The EL-52545 is then connected to the vehicle data link connector (DLC) using the OBD2 Interface Module, which is part of the EL-52545 kit. The stored tire pressure sensor information will then be loaded into the K9 BCM. Using the EL-52545 to learn tire pressure sensors will prevent the vehicle from learning an errant nearby tire pressure sensor from other vehicles in a service facility environment, especially if the tire pressure sensor batteries are low. This is the GM recommended method to learn tire pressure sensors.
1) Turn on EL-52545;
2) Select RDR from the on-screen display;
3) If available, scan the QR code on the vehicle's tire placard or certification label. If QR is not available, select MMY from the on-screen display and manually input the vehicle information.
Make sure the TPMS tool battery is sufficient to complete the learn process. Do not place the tool directly on the valve stem. The tool should be placed against the tire sidewall near the valve stem. The TPMS sensor learn activation procedure may have to be repeated up to three times before determining a sensor is malfunctioning.
4) Approach the vehicle starting with the left front tire and read each tire pressure sensor information by pressing the green trigger button with the EL-52545 located near the tire valve stem. Read each tire pressure sensor in the order identified on the EL-52545 .
5) If any tire pressure sensors do not respond, replace the tire pressure sensor only after several attempts have been made to identify all sensors. An undetected sensor will be identified with "No Sensor Detected" displayed in the table. After sensor replacement rerun RDR procedure. If all sensors do respond, go to the next step.
If any sensors display "Sensor Not Compatible" on the EL-52545 screen, you will need to first make sure compatible sensors are installed on the vehicle.
6) Verify the BAT value for each tire pressure sensor in the table on the EL-52545 is OK. If not, replace the tire pressure sensor and rerun RDR procedure.
7) Verify the pressure and temperature values are reasonable based on the ambient conditions and actual tire pressure. If either value is inaccurate, replace the tire pressure sensor and rerun RDR procedure. If both are accurate, go to the next step.
8) Ignition On/Vehicle in Service Mode.
9) Connect the EL-52545 OBD2 Interface Module to the EL-52545 .
10) Verify the OBDII icon is displayed on the EL-52545 and the green com LED is flashing on the EL-52545 OBD2 Interface Module.
11) Connect the other end of the OBD2 Interface Module to the vehicle DLC.
12) Select OK on the EL-52545 and follow the on-screen instructions.
Tire Pressure Sensor Learn with EL-50448 (Alternative)
When the EL-50448 Tire Pressure Monitor Sensor Activation Tool is used in activate mode, it produces a low frequency transmission that activates the sensor. The sensor responds to a low frequency activation by transmitting in Learn Mode-Remotely Triggered. When the BCM receives a learn mode transmission while in Learn mode, it will assign that sensor’s ID to the location on the vehicle relative to the order in which it was learned.
In the event a particular sensor is activated and the horn does not chirp, it may be necessary to rotate the wheel so that the valve stem is in a different position due to the sensor signal being blocked by another component. Make sure the TPMS tool battery is sufficient to complete the learn process. Do not place the tool directly on the valve stem. The tool should be placed against the tire sidewall near the valve stem. The sensor learn activation procedure may have to be repeated up to three times before determining a sensor is malfunctioning.
1) Ignition On/Vehicle in Service Mode, using vehicle information section in the center stack console, initiate the Tire Pressure Sensors Learn mode by navigating to Tire Pressure (psi) and tap it. Next, press and hold the image of the top vehicle view with four tires for 10 seconds and release. A double horn chirp will sound indicating the Learn mode has been enabled. The left front turn signal will also be illuminated.
2) Starting with the left front tire, activate the sensor by holding the antenna of the tire pressure monitor activation tool aimed upward against the tire sidewall close to the wheel rim at the valve stem location. Press and release the activate button. Ensure that the transmit indicator on the tool indicates that the sensor activation signal is being transmitted. Wait for a horn chirp. If the horn does not chirp, repeat the sensor activation sequence with the tool. Once the horn chirp has sounded, the sensor information is learned and the turn signal in the next location to be learned will illuminate.
3) After the horn chirp has sounded and the right front turn signal is illuminated, repeat the prior step for the remaining three sensors in the following order: right front / right rear / left rear.
4) When the left rear sensor has been learned and a double horn chirp has sounded, the learn process is complete and the BCM exits the Learn mode.
REMOVAL AND INSTALLATION
Tire Pressure Indicator Sensor Replacement (Clamp-in style)
Before the tire is removed from the wheel note the following items:
• When using the tire machine to separate the tire bead from the wheel, position the bead breaking fixture 90 degrees from the valve stem.
• When removing the tire from the wheel, ensure a tolerance is maintained between the tire machine fixture, or irons, tire bead and the sensor.
Removal Procedure
1) Raise and support the vehicle.
2) Remove the tire and wheel assembly.
3) Remove and discard the Tire Pressure Sensor cap.
4) Remove and discard the Tire Valve Front and Rear Stem.
5) Demount the tire from the wheel.
6) If a tire sealant product was used/found within the tire/wheel, use a mild dish soap, clean water and shop cloths to remove the sealant residue from the tire and wheel surfaces.
7) Remove and discard the Tire Pressure Indicator Sensor Nut.
8) Remove the Tire Pressure Indicator Sensor.
9) Remove and discard both the metal and rubber tire pressure indicator sensor washers.
Installation Procedure
1) Ensure that the sealing surfaces of the tire pressure indicator sensor and the wheel are clean of dirt and debris.
2) Install a new rubber tire pressure indicator sensor washer.
3) Install a new metal tire pressure indicator sensor washer.
4) Install the Tire Pressure Indicator Sensor. (The air passage of the tire pressure indicator sensor must face away from the wheel.)
5) Install a new Tire Pressure Indicator Sensor Nut and hand tighten. (Apply light pressure when installing the tire pressure indicator sensor nut to ensure its positioned correctly.)
6) Ensure that the tire pressure indicator sensor is properly oriented and flush with the wheel surface.
7) Mount the tire to the wheel.
8) Install new Tire Valve Front and Rear Stem.
9) Inflate the tire to the proper pressure as indicated on the tire placard.
10) Install new Tire Pressure Indicator Sensor Cap
11) Install the tire and wheel assembly.
12) Remove the support and lower the vehicle.
13) Perform the tire pressure indicator sensor learn procedure.
Tire Pressure Indicator Sensor Replacement (Snap-in style)
Removal Procedure
1) Raise and support the vehicle.
2) Remove the tire and wheel assembly.
3) Demount the tire from the wheel.
4) If a tire sealant product was used/found within the tire/wheel, use a mild dish soap, clean water and shop cloths to remove the sealant residue from the tire and wheel surfaces.
5) Use a suitable tool inserted into the hole of the valve stem to prevent it from rotating.
6) Remove and discard the tire pressure indicator sensor bolt.
7) Remove the tire pressure indicator sensor by pulling it straight off of the valve stem.
8) Remove and discard the valve stem by pulling it through the wheel.
Do not scratch or damage the clear coating on aluminum wheels with the tire changing equipment. Scratching the clear coating could cause the aluminum wheel to corrode and the clear coating to peel from the wheel.
Installation Procedure
Never install the tire pressure indicator sensor on an unapproved wheel. Whenever the Tire Pressure Indicator Sensor is removed from the rim, install a new valve stem and a new bolt. Do not reuse the old parts.
1) Before installation, verify the orientation of the valve stem for the correct position of the tire pressure indicator sensor.
2) Remove the new bolt from the new tire pressure indicator sensor and pull it straight off of the new valve stem.
3) Apply lubricant to the new valve stem.
4) Using a tire valve stem installation tool, pull the valve stem through in a direction parallel to the valve hole on the wheel.
Ensure the flat of the valve lines up with the flats of the snap in the enclosure.
5) Assemble the tire pressure indicator sensor to the new valve stem.
6) Use a suitable tool inserted into the hole of the valve stem to prevent it from rotating.
7) Install and tighten the new tire pressure indicator sensor bolt.
8) Check that the valve stem is concentric and completely seated in the valve stem hole of the wheel.
9) Make sure that there is a gap between the valve stem and the tire pressure indicator sensor.
The tire should not have contact with the tire pressure indicator sensor during installation to prevent a damage of the tire pressure indicator sensor.
10) Mount the tire to the wheel.
11) Inflate the tire to the specified pressure as stated on the tire placard.
12) Install the new dust cap.
13) Install the tire and wheel assembly.
14) Perform the tire pressure indicator sensor learn procedure.
15) Remove the support and lower the vehicle.
TORQUE SPECIFICATIONS
DESCRIPTION
Tire Pressure Indicator Sensor Nut
SPECIFICATION
9 N.m (80 lb in)
