He did say the car might relearn the pressures if enough voltage can be read.
I had the TPMS voltage output checked on each tire and found three of the ,have no voltage output. I was told that if car is close to 100k miles and your in need of tires, replace the TPMS in all the tires to avoid breaking the tires off the rim and having to replace the sensors as the batteries are not seviceable, at a later time.Sooner tahn you would think. I have 108k miles.
I have factory 18 wheels, turns out the TPMS in my all 4 wheels have very low output and all 4 need replacement. Anyone else have to replace all 4 TPMS, one for each tire. I was told they last 100k miles or 5-7 years????
On vehicles equipped with Tire Pressure Monitoring (TPM), one tire pressure sensor is mounted to each wheel 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 serviceable components of the tire pressure sensor are:
Sensor-To-Wheel Seal and Metal Washer
Valve Stem Cap
Valve Stem Core
Valve Stem Nut (with pressed-in washer)
Any time a sensor is installed on a wheel, a new Sensor-To-Wheel Seal , Metal Washer and Valve Stem Nut 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
The TPM sensor can be in one of the following operating modes:
OFF MODE – A new TPM sensor will be in this mode. In this mode the sensor does not transmit periodically on its own. By forcing a transmission from the sensor with the TPM-RKE Analyzer, it will change to the STATIONARY MODE. The sensor will also automatically change from OFF mode to the STATIONARY MODE once it experiences a great increase in pressure (i.e. installation into a wheel/tire assembly and then inflated).
WAL MODE – This is the operating mode the sensor assumes when the vehicle is driven over 15mph (24km/h), but only after the vehicle was previously parked for a duration of 18 minutes or greater. In WAL MODE the sensors transmit every 33 seconds and these transmissions contain left/right information that allows the TPM Module to determine sensor location on the vehicle. WAL MODE lasts for the first 10 minutes of consecutive driving, then NORMAL DRIVE mode ensues.
FACTORY MODE– This is a special case of WAL MODE. If a TPM sensor has just been taken out of OFF MODE, then for the first 3 minutes of the WAL period (10 minutes) the sensors transmit at an accelerated rate of every 10 seconds. After the first 20 drives, then the sensors never again transmit out of FACTORY MODE.
NORMAL MODE – This is the operating mode the sensor assumes after the first 10 minutes of a drive. In NORMAL MODE the sensors transmit every 66 seconds and cease transmitting left/right information.
SERVICE MODE– Once a vehicle stops, the sensors go into SERVICE MODE. After 18 minutes of no driving then the sensors go into the STATIONARY MODE. If the vehicle was stopped for less than 18 minutes and driving resumes, then the sensors go back to the NORMAL MODE.
STATIONARY MODE – When a vehicle has been stopped for more then 18 minutes, then the sensor is forced into STATIONARY MODE. In STATIONARY MODE the sensor never transmits any pressure information. The sensor leaves STATIONARY MODE and enters WAL MODE when the vehicle is driven above 15mph (24km/h).
Each sensor’s (transmitter) broadcast is uniquely coded so that the TPM module can monitor the state of each of the sensors on the four rotating road wheels. The TPM module can automatically learn and store the sensor’s ID while driving “within 20 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. The TPM module can also learn the sensor's ID using a the Scan Tool.