2011 Task #5: Chilton's!

Woot!  My wife's car has finally appeared in the Chilton's manuals!  Saturn's Astra came out just a year before the company went under, and it has taken a long time for some of the information to appear.  I originally tried to look up information on the automated tire-pressure system (TPS) about 6 months after we bought the car, but even Chilton's didn't have any info for me.  I've thoroughly dog-eared every piece of maintenance-related literature we had looking for info on various systems that the vehicle has, but on which (until now) I hadn't been able to find much public-access info.  Huzzah for Chilton's online! {click, click, copy, paste, print...}  I have liked their interface since it became available, and even since the early stages it has been pretty easy to use (as long as you know what to call what you're looking for!)

The tire pressure monitor receiver receives a radio frequency (RF) transmission from each tire pressure sensor. Each sensor RF transmission contains its own unique identification (ID) code that must be learned into the tire pressure monitor receiver memory. Once all 4 IDs have been learned and vehicle speed is greater than 32 km/h (20 mph), the tire pressure monitor receiver continuously compares IDs in received transmission to its learned IDs to determine if all 4 sensors are present. If the tire pressure monitor receiver detects a low tire pressure condition or a malfunction in the system, it will send a serial data message to the instrument panel cluster (IPC) requesting tire pressure monitor indicator illumination.

The tire pressure monitor (TPM) system warns the driver when a significant loss, or gain of tire pressure occurs in any of the 4 tires and will illuminate the instrument panel cluster (IPC) tire pressure monitor indicator icon.

The system uses the instrument panel cluster (IPC), tire pressure indicator receiver, a radio frequency (RF) transmitting pressure sensor in each wheel/tire assembly, and the serial data circuit to perform the system functions. Each sensor has an internal power supply with a 10 year service life.

When the vehicle is stationary, the sensors internal accelerometer is inactive, which puts the sensors into a stationary state. In this state the sensors sample tire pressure once every 30 seconds and do not transmit at all if the tire pressure does not change. As vehicle speed increases, centrifugal force activates the sensors internal accelerometer causing the sensors to go into rolling mode. In this mode, the sensors sample tire pressure once every 30 seconds and transmit in rolling mode once every 60 seconds. The tire pressure indicator receiver receives and translates the data contained in each sensors RF transmission into sensor presence, sensor mode, and tire pressure.

The sensors continuously compare their last pressure sample to their current pressure sample and will transmit in re-measure mode if a 8.3 kPa (1.2 psi) change in tire pressure has been detected in either a stationary or rolling state. When the TPM system detects a significant loss, or gain of tire pressure, the tire pressure monitor indicator icon is illuminated on the IPC. The illuminated indicator icon can be cleared by adjusting the tire pressures to the recommended kPa/psi and driving the vehicle above 32 km/h (20 mph) for at least 2 minutes.

The tire pressure indicator receiver has the ability to detect malfunctions within the TPM system. In the event a DTC is set, the tire pressure monitor indicator icon on the IPC will flash for 1 minute and then remain illuminated after the ignition is turned ON and the IPC bulb check has been completed.