ACDelco GM Original Equipment Tire Pressure Monitoring Sensors (TPMS) are battery powered sensors located in the tire that monitor the vehicle’s tire pressure, and warn the driver when pressure falls more than 25% below the manufacturer’s recommendations (normally through a slow pressure loss). The sensor is connected with the valve stem, and by way of Radio Frequency (RF) technology, sends pressure updates to the vehicle’s on-board computer. Tire pressure is displayed on the vehicle’s Driver Information Center (DIC), or when low, a warning lamp might be illuminated to warn the driver. Federal Regulations require that new cars and light trucks be equipped with TPMS starting in 2008. Do I really need a tire pressure sensor?
Yes, you cannot always tell when a tire is under-inflated by just looking at it. Properly inflated tires help your vehicle provide maximum fuel efficiency. If the battery dies on my tire pressure sensor can I just replace it? No, once the battery dies the entire sensor must be replaced.
Is there a sign to let me know when to replace my tire pressure sensor? Yes, if the TPMS light appears as a BLINKING yellow lamp for more than one minute and then stays on solid, then diagnostic service is needed and one or more sensors may need to be replaced. If TPMS is not functioning properly, it cannot detect or signal a low tire condition. Some vehicles may also display ‘Service Tire Monitor System’ on the driver information center. Will the tire pressure sensor indicate if I have over-inflated my tires?
No, it is important to look at the PSI number in the inside door panel of your vehicle to make sure you get the proper tire inflation, and most newer cars will let you check your PSI right on your vehicles dashboard. Is there a difference between a Low Tire and a system malfunction? A Low Tire telltale will be on solid immediately after KEY ON, and will be accompanied by a CHECK TIRE PRESSURE message in the Driver Information Center (if equipped). A system malfunction causes the telltale to flash for the first 60 seconds of a KEY ON event, and then go solid.
Tip: These behaviors repeat at each KEY ON cycle. The best way to diagnose the vehicle (if you're not sure which warning is being displayed) is to KEY OFF and KEY ON again while watching the telltale and DIC messages.
Is Sensor Learning required? Sensor Learning should be done when the vehicle’s tires are rotated (since sensor position on the vehicle has changed) or when a sensor is replaced/a new sensor is installed (since a new ID has been introduced to the vehicle). Sensor Learning is not required when simply correcting the tire pressure resolves the vehicle problem. Is there a reason why there are dashes (- -), or a pressure value of 148 PSI (1020 kPa), sometimes displayed after a battery disconnect? These displays come up after a battery disconnect/reconnect because the system is waiting for updated pressure information to be sent from the tire pressure sensors. As each sensor transmits its information, the display is updated appropriately.
Note that when dashes or 148 PSI (1020 kPa) are displayed after a battery disconnect/reconnect, the System Malfunction warning is NOT displayed - because the system is still working properly, and simply waiting for updated information from the sensors. Driving the vehicle above 20 mph (32 km/h) for 2 minutes gets the sensors talking, and restores the correct pressure values to the display. It is also possible to restore the values by using the J-46079 TPM tool, using the ‘Activate’ function at each tire to activate the sensor (it is NOT necessary to put the system into Learn mode, in this special case). Tire pressure sensors can be damaged if you drive on a flat tire for an extended period of time. Make sure to get your tire pressure sensor checked if this ever happens. It is also important that tire valve components be replaced whenever a tire is removed from the wheel. This will restore proper sealing of the sensor and ensure the integrity of the TPMS sensor and valve.
Low Air Pressure Sensor
Maintaining proper tire inflation level is so important that, beginning with the 2008 model year, Tire Pressure Monitoring Systems (TPMS) are now U.S. Government mandated on most new vehicles.