Principles of Operation
The Tire Pressure Monitoring System (TPMS)
has the ability to monitor the air pressure of all five tires. The tire-mounted pressure sensors transmit signals to the TPMS module by using the valve stem as an antenna. These transmissions are sent approximately every 60 seconds when the vehicle speed exceeds 32 km/h (20 mph)
. The TPMS module compares each tire pressure sensor transmission against low and high pressure limits. If the TPMS module determines that the tire pressure has exceeded the limit, the TPMS module communicates on the SCP network to the vehicle message center, which then displays a warning message. The system is not affected by wheel and tire rotation.Vehicle Message Center TPMS Messages
The vehicle message center sometimes displays messages that cannot be resolved by the customer. Treat these messages as TPMS system faults that must be serviced. Refer to the symptom chart for the following messages:
Displayed when one or more tires have very low pressure. When this warning message is displayed, a warning chime will sound reminding you to stop the vehicle as soon as safely possible and check the tires for correct pressure, leaks and damage.
Check Tire Pressure
Displayed when any of the tire pressures are high or low.
Check Spare Tire Pressure Displayed when the spare tire pressure is high or low.
Tire Pressure Sensor Fault
Displayed when a tire pressure sensor is malfunctioning.
If the customer requests that the TPMS be turned off, it can be done by configuring the message center through the Instrument Cluster (IC) , using the scan tool.
As you can see this sytem is dependant on air pressure not wheel speed. Some tire pressure systems are designed to monitor wheel speed and if it sees a difference in wheel speed it determines that that there is a low tire. This system has pressure sensors in the tires. It is a part of the valve stem. If you have the air pressure in the tire that the door sticker says you need then the problem is either a bad sensor or module.
Here is the pinpoint test for a low tire pressure warning. You will need a scan tool that can read body codes in order to properly diagnose the system.
Again the tire circumference will not turn on the message, but a bad sensor could and low air pressure will.