Tire Monitoring System - Operation/Functionality
INFORMATIONBulletin No.: 09-03-16-003
Date: May 26, 2009
Subject: Tire Pressure Monitoring (TPM) System Operation, Importance of Following Proper PDI Procedures and Understanding Possible Customer Concerns
Models:
2009-2010 Pontiac Vibe
Attention:
The TPM system in the Pontiac Vibe has several unique operating characteristics. This system does not share components with other GM vehicles. The system must be Initialized at the time of Pre-Delivery Inspection (PDI). This bulletin is designed to assist with an overall understanding of the systems capabilities and proper use.
Service Concerns
Some confusion exists both with customers and with the GM service community as to the proper operation and functionality of the tire pressure monitoring (TPM) system used on the Pontiac Vibe. This system does not share componentry with other GM tire pressure monitoring systems and differs in certain design features. By following proper procedures at the time of delivery, and understanding the correct operation of the system, you will be able to properly inform customers and minimize any customer concerns.
System Description
A tire pressure sensor/transmitter is installed within each tire and wheel assembly. These sensors/transmitters broadcast measured air pressure, temperature and the transmitter ID number to the tire pressure warning receiver as radio waves. The tire pressure warning receiver then sends this information to the tire pressure warning ECU.
The sensor transmitter ID numbers are compared to the expected ID numbers pre-programmed at the factory into the tire pressure warning ECU. If the transmitter ID numbers match, the ECU accepts the information and constantly monitors these transmissions.
The tire pressure warning ECU compares the actual measured air pressure values with an expected or standard value. When the actual value is 27.6-34.5 kPa (4-5 psi) less than the standard value registered in the tire pressure warning ECU, the low tire pressure warning light on the cluster comes on steady.
This system includes an under dash tire pressure warning "set" switch to manually change the standard value for use with different air pressure values required for optional tires.
TPM "Set" Button Location
Important
The "set" button establishes the preferred air pressure value the system recognizes from that point on. This button should NOT be used to command the low tire pressure indicator light off. Pressing the button during a low tire pressure event may command the light off and ESTABLISH A NEW LOWER ACCEPTABLE AIR PRESSURE VALUE.
Tire Pressure Monitor Set Switch
History
A tire pressure set switch (located under the I/P) is included as part of the TPM system. It is believed that a misunderstanding of this switch's operation may exist. Pontiac dealers may still be familiar with the tire pressure monitor reset switch used on various GM models that incorporated a passive TPM system using wheel speed monitoring to mathematically sense a low tire condition. An example is the 1997-2003 Grand Prix models which had a tire pressure reset switch of the same style and in the same location as the set switch on the Vibe. The switch in the previous vehicles required resetting anytime the "low tire" lamp came on. It corrected the concern and was the only way to command the lamp off. This is NOT how the system operates on the Vibe.
Proper Operation of the Reset Switch
The reset switch on the Vibe is NOT used to command the I/P warning light OFF. It's function is to program the recommended tire pressure values from the tire and loading information label into the tire pressure warning ECU.
- After depressing the tire pressure reset switch, the on-wheel tire pressure sensor/transmitter measures the inflation pressure of the tire and registers the values that are transmitted into the tire pressure warning ECU. The initialization process is completed when signals from all the tires have been received. It may take up to seven minutes to complete the process.
- Whatever the actual air pressure is in each tire at the time the set button is pressed becomes the standard value in the tire pressure warning ECU. This adaptability allows for the customer to continue to have proper functionality of the system in the event tire and wheel changes (by the customer) are made that have different air pressure requirements.
Readying the System at PDI (System Initialization)
The TPM system MUST be properly initialized at the time of vehicle delivery in order for the TPM system to function as expected and outlined in the vehicles Owner Manual.
Notice
The wheel-mounted TPM sensors/transmitters are activated at the manufacturing plant. Only the initialization process as shown below is required during PDI.
Warning
Setting the air pressure in the tires to the values indicated on the tire and loading information label is critical to the system functioning as intended.
1. Adjust all tires (except the spare tire) to the standard tire inflation pressure as indicated on the tire and loading information label on the vehicle.
2. Cycle the ignition switch to the "IG-ON" position and check that the low tire pressure warning light is off.
3. Push and hold the tire pressure warning "SET" switch until the low tire pressure warning light blinks three times and then turns off, indicating that the system initialization has begun.
Important
The ignition switch MUST be left in the "IG-ON" position for AT LEAST SEVEN MINUTES for initialization to complete.
4. Cycle the ignition switch to the "OFF" position and then to the "IG-ON" position.
5. Verify that the tire pressure warning light is off. If the lamp is on, repeat the procedure.
Important
If the above procedure is not successfully completed, the TPM system WILL NOT function as intended.
Notice
If the data scan tool is in communication with the tire pressure ECU, the tire pressure "set" button may not function as intended.
Important
Under some circumstances the diagnostic scan tool information screen may indicate that one or more of the TPM sensor values is 0 kPa/psi and -40°C/F. DO NOT REPLACE SENSORS FOR THIS CONDITION. This condition may be caused by improper reception of the tire pressure data or attempting communication with the tire pressure warning ECM during initialization. Please repeat the initialization procedure (waiting seven minutes) and retest.
Tire Pressure Light Indications During Customer Use
At KEY ON (without starting the vehicle):
Steady Solid Glowing TPM Indicator
If the TPM indicator light appears as a steady glowing yellow lamp (as above), the system is functioning properly and you should ADD air to the tires to correct this condition.
Notice
Once the TPM indicator is lit, the system may not command the warning light off unless the tire is returned to the pressure indicated on the tire and loading information label.
Note
Maintaining proper tire pressures is an owner maintenance item and is not covered under warranty.
Blinking TPM Indicator
If the TPM indicator appears as a BLINKING yellow lamp for ONE MINUTE and then stays on solid, diagnostic service is needed. Refer to Tire Pressure Monitoring in SI for additional information.
Important
Do not use the TPMS reset button to turn off the light. The system will update and the light will turn off when all tire pressures have been adjusted followed by a short distance drive.
Important
Tire monitor sensors are not learned to a specific vehicle corner. Do not perform a TPM reset after tire rotation. The TPMS set button must only be used during pre-delivery inspection by the dealer to initialize the system (after all tire pressures have been adjusted properly) or when a tire pressure monitor system component is replaced. The J 46079 tool does not work on Vibe TPM sensors. You WILL NOT be able to receive sensor ID number information using the J 46079. A TPMS relearn on the Vibe must be performed with a Tech 2(R) to set the TPMS module in the learn mode. The TPMS sensor IDs are entered through the Tech 2(R). Refer to SI for further Vibe TPMS information.
Frequently Asked Questions:
Q: What is the lower limit the tire pressure monitoring system can be set for?
A: The lowest pressure the system will accept is approximately 193 kPa (28 psi) +/- 13.8 kPa (2 psi). If you should attempt to push the set button to establish a pressure below 193 kPa (28 psi) +/- 13.8 kPa (2 psi), the TPM warning indicator on the I/P may glow steady.
Q: Can you set the required TPM air pressure values from the Data Scan Tool?
A: No. You may monitor the air pressure and temperature as reported by each on-wheel sensor. You may also change the TPM sensor ID codes if sensor replacement is required.
Q: What if my tire pressure light comes on and stays on solid with a low tire pressure icon?
A: Simply add the proper amount of air to your tires. Reference the Tire and Loading Information label in the driver door opening for the recommended tire pressures. Once the tires are properly filled with air, drive the vehicle and the message/light should go off.
Q: What if my tire pressure light comes on and stays on solid with a low tire pressure icon, I have checked the Tire and Loading Information label and adjusted the tire pressures accordingly, but the light remains on?
A: This may be a case where the system was set at a higher air pressure value upon vehicle delivery, or the "set" button may have been inadvertently pressed by the customer (such as while vacuuming) with warm tires, thus establishing too high an initial pressure value. With the vehicle tires cold, set the pressure as indicated on the Tire and Loading Information label, and press the set button until the low tire pressure icon flashes. Leave the vehicle ON for 7 minutes or drive normally for the same amount of time. This action should correct the condition.
Q: What if my tire pressure light comes on and I add "some" air because I didn't have a tire gauge handy but the light remains on?
A: Once the low tire pressure light has been turned on, the Vibe TPM system may not turn the lamp off until the tires are returned to the full value indicated on the Tire and Loading Information label.
Q: The air pressure measurement I read with my tire gauge does NOT match the reading I can view with the Tech 2(R) scan tool?
A: The air pressure readings are accurate to approximately +/- 13.8 kPa (2 psi). It is NOT uncommon to see small differences between the reported pressure data and what is read on a tire pressure gauge. DO NOT REPLACE tire pressure sensors for this condition.
Disclaimer