What kind of tire pressure sensors are on a 2000 olds alero and are they located inside the wheel?

{: ) The 2002 Oldsmobile uses the TIM system. Here is an overview of how it works:
The tire inflation monitoring (TIM) system detects the differences in tire rotation speeds that are caused by changes in tire pressure. The TIM may not alert the driver if the pressure in more than one tire is high or low. The TIM also may not operate properly if the spare tire is in use.
The TIM system can alert the driver when a large change in the pressure of one tire exists. The system only detects a low pressure condition while the vehicle is being driven.
The LOW TIRE PRESSURE indicator turns ON in the instrument cluster if the tire pressure in one tire becomes 12 psi (55 kPa) lower or higher than the other 3 tires and the ignition switch is in the ON position. The message does not appear if more than one tire is low or high, or if the system is not calibrated properly. The system does not inform the driver which tire is low. In order to clear this message, equalize the tire pressures in all 4 tires and perform the Tire Inflation Monitor Resetting. In addition, the indicator may come ON if a low voltage condition is present.

In other words, this is not like the TPM (Tire Pressure Monitoring) system that is being used in later model vehicles, wherein the TPM sensors are inside the wheel, integrated to the tire valve. The TPM sensors detect changes in tire pressure and temperature, and sends out radio signals to the RCDLR, to be decoded by the BCM and the instrument cluster.