Originally Posted by MMZ_TimeLord
Remember that the TPM also will come on when a single tire is 10% (I think) different from the rest of the tires. This is an indicator to the system that you have one tire with a slow leak and to check it before it becomes a violent blowout on the freeway.
Cheers!
Jody, that is not correct. The TPM light trips when any tire drops below the threshold pressure. Low pressure is defined as 26 PSI. I couldn't find a reference to Critical Pressure. Here's the quote from the service manual:
DESCRIPTION
This vehicle has a tire pressure monitoring (TPM) system.
It is there to alert the driver when air pressure in any of the vehicle’s four tires falls below a predetermined threshold. It alerts the driver with a lamp in the instrument cluster.
The tire pressure monitoring system utilizes transmitters that are located in the valve stem of each tire to communicate the tire pressure condition to the module.
If a tire has low air pressure, an indicator light on the instrument cluster is illuminated. The vehicle operator must check the tire pressure of each tire in order to determine which tire has a low pressure condition.
The garage door opener/tire pressure monitoring (TPM) module has a microprocessor controller that can monitor the transmissions from the sensor/transmitters anytime the ignition is on. It can store the last 32 transmissions. There are two important values included in these transmissions. They are:
² Why the transmission was sent,
² Low Tire Pressure
The module compares the transmitted tire pressure from the sensor to the two pressure thresholds (low pressure or critical pressure). If the module determines that the tire pressure transmitted is below the low or critical pressure thresholds, it will signal for the “Low Tire” pressure warning lamp to come on.