SENSOR-TPM
DESCRIPTION
On vehicles equipped with Tire Pressure Monitoring (TPM), one tire pressure sensor (6) is mounted to each wheel (5) in place of the traditional tire valve stem. Each sensor has an internal battery that lasts up to 10 years. The battery is not serviceable. At the time of battery failure, the sensor must be replaced.
The TPM system operates on a 315 MHz radio frequency. The 315 MHz sensors can be easily identified by a white outline oval (black center) insignia (3) on the sensor body.
The Export TPM system operates on a 433 MHz radio frequency. The 433 MHz sensors can be easily identified by either a solid white oval insignia (3) on the body or . . .
. . . a solid white oval insignia (3) with 433 printed in the center. The sensors are identical except for the oval insignia. The 433 MHz sensors can either have a black or grey sensor body.
CAUTION: 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.
NOTE: Sensors may be identified by valve stem cap color. From the factory, 315 MHz sensors have a gray valve stem cap while 433 MHz sensors have a black valve stem cap. Otherwise, once mounted inside a tire and wheel assembly you are not able to visually tell the difference between a 315 MHz and 433 MHz sensor. The tire must be dismounted allowing visual inspection of the sensor body.
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). Do not attempt to install a tire pressure sensor in an aftermarket wheel. If aftermarket wheels are installed and do not contain tire pressure sensors, the system will not function properly and the driver will be continuously notified of a system malfunction.
The serviceable components of the tire pressure sensor are:
- Sensor-To-Wheel Seal (2) and Metal Washer (1)
- Valve Stem Cap (4)
- Valve Stem Core
- Valve Stem Nut (with pressed-in washer) (3)
NOTE: Any time a sensor is installed on a wheel, a new Sensor-To-Wheel Seal (2), Metal Washer (1) and Valve Stem Nut (3) must be installed to ensure air tight sealing. A service kit is available.
The valve stem caps and cores are specifically designed for the tire pressure monitoring sensors. Although similar to standard valve stem caps and cores, they are different. The valve stem cap has a special seal inside to keep moisture and corrosion out. The valve stem core has a special nickel coating to protect from corrosion.
OPERATION
The battery operated tire pressure sensor is both a transmitter and a receiver. The TPM sensor can be forced to transmit by using a special tool such as a TPM-RKE Analyzer, or from a transponder (Refer to 22 - TIRES/WHEELS/TIRE PRESSURE MONITORING/TRANSPONDER - OPERATION). The TPM-RKE Analyzer has the ability to change the sensor’s operating mode to PARK MODE and to help diagnose a faulty TPM sensor. Using a TPM-RKE Analyzer can take up to a minute to force a transmission from a sensor.
The TPM sensor can be in one of the following operating modes:
- SLEEP MODE – This is the operating mode of a new TPM sensor. If placed on the vehicle as a road tire, the sensor will transmit once every 20 seconds when the vehicle is driven at speeds over 15 mph (24 km/h). If the vehicle is not moving, the sensor will only transmit on a pressure change greater then 1 psi (6.9 kPa). Driving the vehicle continuously at this speed for more then 4 minutes, and then stopping the vehicle will change the sensor state into PARK MODE.
- PARK MODE – This is the correct operating mode when the vehicle is not moving. The sensor will transmit once every 13 hours to update the WCM, or will transmit on a 1 psi (6.9 kPa) delta change. The sensors will internally take a measurement of the tire pressure every minute to determine a change in tire pressure.
- 30 BLOCK MODE – If the vehicle has been stopped for more then 20 minutes, or if the sensor’s operating mode was forced to Park Mode using a TPM-RKE Analyzer, the sensor’s operating mode will transition from PARK MODE to 30 Block Mode once the vehicle is driven over 15 mph. In this mode, the sensor will transmit once every 15 seconds when the vehicle is driven at speeds over 15 mph (24 km/h) for the first 30 transmissions. After about 8 minutes of continuous driving above 15 mph (24 km/h), the sensor’s mode will change to DRIVE MODE.
- DRIVE MODE – In this mode, the sensor will transmit once every minute when the vehicle is driven at speeds over 15 mph (24 km/h). At any time the vehicle speed drops below 15 mph, the sensor will revert back to PARK MODE. The sensor mode will still be in drive mode when the sensor reaches speeds over 15 mph (24 km/h), unless the vehicle has been stationary for more then 20 minutes.
Each sensor’s (transmitter) broadcast is uniquely coded so that the wireless control module (WCM) can monitor the state of each of the sensors on the four rotating road wheels. The WCM can automatically learn and store the sensor’s ID while driving “within 10 minutes continuously above 15 mph (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.
CAUTION
CAUTION: The use of tire sealants is strictly prohibited for vehicles equipped with the Tire Pressure Monitoring system. Tire sealants can clog tire pressure sensors.
CAUTION: Any time a sensor is to be installed in a wheel, it is necessary to install a new sensor-to-wheel seal, metal washer and valve stem nut, to ensure air tight sealing.
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: When installing the valve core, be sure to tighten the core to specifications (Refer to 22 - TIRES/WHEELS/WHEELS - SPECIFICATIONS). Overtightening by a little as three or four inch pounds can damage the sensor.
CAUTION: Do not attempt to install a tire pressure sensor in an aftermarket wheel. Use tire pressure sensors in original style factory wheels only. If aftermarket wheels are installed, and therefore do not contain tire pressure sensors, the system will not function properly and the driver will be continuously notified of a system malfunction.
NOTE: TPM thresholds have been established for the original tire size equipped on the vehicle. Use original size tires only to maintain system accuracy.
REMOVAL
1. Raise and support vehicle. (Refer to LUBRICATION & MAINTENANCE/HOISTING - STANDARD PROCEDURE)
2. Remove wheel mounting nuts (3), then tire and wheel assembly (1). (Refer to 22 - TIRES/WHEELS - REMOVAL)
CAUTION: The cap used on this valve stem contains an O-ring seal to prevent contamination and moisture from entering the valve stem. Retain this valve stem cap for reuse. Do not substitute a regular valve stem cap in its place.
CAUTION: The valve stem used on this vehicle is made of aluminum and the core is nickel plated brass. The original valve stem core must be reinstalled and not substituted with a valve stem core made of a different material. This is required to prevent corrosion in the valve stem caused by the different metals.
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. That includes both front and rear beads of the tire.
b. When preparing to dismount the tire from the wheel, carefully insert the mounting/dismounting tool at the valve stem ± 10°, then proceed to dismount the tire from the wheel. Use this process on both the upper and lower tire beads.
4. Remove sensor nut (3) retaining sensor to wheel. While removing nut, hold pressure against rear of metal valve stem to keep valve stem from pushing rearward, damaging antenna strap.
5. Remove sensor (1) from wheel (2).
INSTALLATION
NOTE: Anytime a TPM sensor is reused on a wheel, it is necessary to install a new sensor-to-wheel seal (2), metal washer (1) and valve stem nut (3), to ensure proper sealing around the sensor valve stem (6).
1. Wipe the area clean around the sensor/valve stem mounting hole in the wheel (5). Make sure the surface of the wheel is not damaged.
CAUTION: To avoid damaging the sensor antenna strap (1), hold pressure against the rear of the metal valve stem (2) while the sensor is inserted through the wheel mounting hole and the nut is installed.
2. Insert the sensor (1) through the wheel (2) as shown keeping pressure against the rear of the metal valve stem (See Arrow). The potted side of the sensor is to be positioned toward the wheel. Do not attempt to mount the sensor otherwise, damage may occur.
3. Install the sensor nut (with pressed-in washer) (3) by hand.
NOTE: Before tightening the sensor nut, push downward on the sensor housing (2) in an attempt to make it flush with the interior contour of the wheel (1).
4. While holding the sensor in position, tighten the sensor nut to 6.5 N·m (58 in. lbs.).
CAUTION: Over-torquing the sensor nut by as little as 12 N·m (106 in. lbs.) may result in sensor separation from the valve stem. Under this condition, the sensor may still function. However, the condition should be corrected immediately.
5. Mount the tire on the wheel following the tire changer manufacturers instructions, paying special attention to the following to avoid damaging tire pressure sensor:
a.
b.
6. Adjust air pressure to that listed on the Tire Inflation Pressure Label (Placard) provided with the vehicle (applied to driver's side B-pillar). Make sure the original style and color valve stem cap is securely installed to keep moisture out of the sensor.
7. Install the tire and wheel assembly (1) on the vehicle (Refer to 22 - TIRES/WHEELS - INSTALLATION). Tighten wheel mounting nuts (3) to 135 N·m (100 ft. lbs.).
8. Lower vehicle.
9. Once vehicle has been stationary for more than 19 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.
NOTE: If a sensor cannot be trained, refer to appropriate diagnostic information.