Ian, I own a 2001 Bonneville which has the "Tire Pressure" feature. When I check the readout, it says "Normal". Does this mean that the tire pressure is at the right level or does it merely mean that all 4 tires have the same pressure? If the latter and I had to add more air in all four tires, would the readout still read "Normal" as long as I brought all tires up to the same level? Or would the gauge have to be reset somehow?
Thanks in advance. - Sting Ray
After adding air pressure in any tire, match them up, and then reset the automatic gauge system.
---Bob Gross---
"Sting Ray" wrote
It means that there is no one single tire that is 10 psi higher or lower then the other three tires. So you can see that it's not designed to be a real accurate sensor, just lets you know when one tire is getting really low.
I'll paste in the sections from the manual, better to let GM explain its own system.
Tire Pressure Monitor Description and Operation The Tire Pressure Monitor (TPM) system alerts the driver when a large change in tire pressure exists while the vehicle is being driven. The TPM system uses the Electronic Brake Control Module (EBCM), Antilock Brake System (ABS) wheel speed sensor inputs, class 2 serial data circuit, Systems monitor, or the Driver Information Center (DIC) (if equipped) to perform the system functions. The EBCM contains software to calculate relative tire pressure differences. The software requires approximately 30 minutes of straight line driving in three different speed ranges to complete the calibration process to have full capability for detecting a tire pressure condition. The speed ranges are as follows:
a.. 24-64 km/h (15-40 mph) b.. 64-113 km/h (40-70 mph) c.. 113-145 km/h (70-90 mph) Each speed range has 2 modes of tire pressure detection.
a.. Monitor Mode 1 b.. Monitor Mode 2 The EBCM learns the tire pressure calibration for each speed range independently. In Monitor Mode 1, the EBCM has only partially learned the tire pressure calibration for the speed range and has limited detection capability for a tire pressure conditions. In Monitor Mode 2, the EBCM has fully learned the tire pressure calibration for the speed range and has full detection capability for a tire pressure condition. Once the TPM system has fully learned the tire pressure calibration the EBCM monitors the ABS wheel speed sensor inputs, which will all be the same as the learned calibration if the tire pressures stay the same. If the pressure increases or decreases in one tire so to will that tires circumference and radius, which causes that wheel speed sensor input to change. The EBCM recognizes this change in wheel speed as a tire pressure condition. If the pressure in one tire becomes at least 69 kPa (10 psi) higher or lower than the other three the EBCM turns on the TIRE PRESS indicator on the systems monitor. On vehicles equipped with a DIC the EBCM commands the DIC to display the CHECK TIRE PRESSURE warning message via a class 2 serial data circuit. The DIC message nor the Systems Monitor indicator appears if more than one tire pressure is high or low, or if the system is not properly calibrated. The system does not alert the driver to which tire pressure is high or low. If the tire pressures are at the specified psi the TIRE PRESSURE NORMAL message is displayed when selected on the DIC. To clear the TIRE PRESS indicator, or the CHECK TIRE PRESSURE message, refer to Tire Pressure Monitor Reset Procedure .
Tire Pressure Monitor Reset Procedure
Important There are 3 ways to reset the Tire Pressure Monitor (TPM) system. After resetting, the TPM system requires up to 30 minutes of straight line driving in each of the 3 speed ranges to complete the calibration process, for more information, refer to Tire Pressure Monitor Description and Operation . If the TPM system does not reset using the Systems Monitor procedure, refer to Low Tire Pressure Indicator Does Not Reset . If the TPM system does not reset using the Driver Information Center (DIC) procedure refer to Driver Information Center (DIC) Switch(es) Inoperative in Instrument Panel, Gages, and console. If DTC C1245 remains current, refer to Diagnostic System Check - Tire Pressure Monitoring .
Using the Systems Monitor 1.. Set all tire pressures to the recommended kPa/psi. Refer to Tire Inflation Pressure Specifications in Maintenance and Lubrication, or to Tire Placard in General Information. 2.. Turn ON the ignition, with the engine OFF. 3.. Press and hold the TIRE PRESS RESET button until the TIRE PRESS indicator begins to flash. 4.. Release the TIRE PRESS RESET button and the TIRE PRESS indicator will turn off. 5.. Use the scan tool in order to clear the TPM DTC. Using the DIC, if equipped 1.. Set all tire pressures to the recommended kPa/psi. Refer to Tire Inflation Pressure Specifications in Maintenance and Lubrication, or to Tire Placard in General Information. 2.. Turn ON the ignition, with the engine OFF. 3.. Press the MODE button until TIRE PRESSURE is displayed. 4.. Press and hold the RESET button until TIRE PRESSURE RESET is displayed. 5.. Release the RESET button, TIRE PRESSURE NORMAL is displayed. 6.. Use the scan tool in order to clear the TPM DTC.
Hope that helps.
Ian
Thanks Bob! Ian just advised me how to reset the system if necessary.
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