Tpms
NOT! As soon as I started driving the display switched back again. WTF! Any techno, gizmo guys out there have any ideas?
Last edited by kodpkd; Sep 9, 2025 at 08:00 PM.
Unless you are 100% sure your gage is accurate, it's hard to tell which is accurate.
But it doesn't really make a difference.
If you want the 30lbs that your gage indicates, just fill till the tpms indicate 27.
Sometimes, the electronics just weird out.
The Corvette I think has a system that "auto learns" and so the sensors report where they are relative to a few antennas in the car. I'm not up on the details on the C7 (I'd have to read the service manual), but back when I worked on TPMS with Chrysler they had 3 antennas and they triangulated the signal location to know which wheel was which. Perhaps the antennas are confused (as in there physical location doesn't match where the car thinks they are). Is the wrong sensor to wheel a problem with multiple TPMS setups?
Some cars hard learn them and you need to re-learn them whenever you rotate tires (or have the display be wrong). These systems are gradually going away as the auto-learn systems get cheaper.






2014 z51!!

no, i trust the system discount tire uses, showing pressure i want + shows pressure before adding!!
The Best of Corvette for Corvette Enthusiasts






coming out of the auto carwash this morning, discount tire was just opening!!
dic: 3 displayed 27, one 26, which is the same pressures the discount machine was showing before 32 all around!!
Tire Pressure Monitor Description and Operation
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 allows the driver to display the individual tire pressures and their locations on the driver information center (DIC).
The system uses the body control module (BCM), driver information center (DIC), instrument panelcluster (IPC), remote control door lock receiver (RCDLR), 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 RCDLR receives and translates the data contained in each sensors RF transmission into sensor presence, sensor mode, and tire pressure. The RCDLR sends the tire pressure and tire location data to the DIC via the serial data circuit where they are displayed.
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 and if equipped, a check tire pressure type message is displayed on the DIC. Both the indicator icon and DIC message can be cleared by adjusting the tire pressures to the recommended kPa/psi and driving the vehicle above 40 km/h (25 mph) for at least 2 minutes.
If power is disconnected from the RCDLR or if the vehicle battery is disconnected each TPM sensor ID is retained but all of the tire pressure information is lost. Under these circumstances the RCDLR cannot assume that the tire pressures were maintained over an unknown period of time. If equipped, the DIC will display all dashes and the scan tool will indicate a default tire pressure value of 1020 kPa (148 psi) for each tire. Driving the vehicle above 40 km/h (25 mph) for at least 2 minutes will activate the sensors causing the DIC to display the current tire pressures. The EL-46079/J-46079 - tire pressure monitor diagnostic tool may also be used to activate the sensors as well.
The RCDLR 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. Any malfunction detected will cause the DIC to display a service tire monitor system type message. For more information on other functions of the RCDLR, refer to Keyless Entry System Description and Operation See: Keyless Entry > Components > Keyless Entry System.
#07-03-16-004D: TPM System Overview, Diagnosing Tire Pressure Monitor System (TPM) Concerns and TPM Frequently Asked Questions (FAQ) - (Jan 10, 2022) Subject: TPM System Overview, Diagnosing Tire Pressure Monitor System (TPM) Concerns and TPM Frequently Asked Questions (FAQ)
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GM Passenger Cars and Light Duty Trucks
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This bulletin has been revised to add the 2013-2022 Model Years and update applicable information throughout, including Warranty Information. Please discard Corporate Bulletin Number 07-03-16-004C.
Customer Concerns and ConfusionWhen a customer comments on a condition related to tire pressure monitoring, it is very important to distinguish between Check Tire Pressure / Low Tire Pressure conditions and Service Tire Monitor system issues. Understanding the difference between the two distinct conditions will help you distinguish between normal system operation (tire needs air) and a system malfunction.
There are two important differences between a Check Tire Pressure / Low Tire Pressure message/light and a Service Tire Monitor message light:
- A Check Tire Pressure / Low Tire Pressure message/light will stay on solid and no system codes are set. The TPM system is operating as designed. Correcting the tire pressure will resolve the issue.
- A Service Tire Monitor message/light will blink and system codes WILL set. There is a condition that should be diagnosed and corrected.
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Service Tire Monitor System (light blinks, then stays on)
The Tire Pressure Light will blink for about one minute and a Service Tire Monitor message will be displayed when a system malfunction occurs. For example: If one or more tire pressure sensors does not transmit information for 18 minutes of driving, the TPM system WILL set a code, display a message, and BLINK the light for about a minute, after which the light will stay on solid for the remainder of the ignition cycle. If the system fault is intermittent, the message/light may also be intermittent – on during some ignition cycles, off during others.
Low Tire Pressure Warning (light stays on solid)
If the TPM system detects a tire pressure below the threshold, the Check Tire Pressure message and the Tire Pressure Light will come on and stay on. The message and light may be intermittent in nature, especially during cold weather.
Conditions That Will Cause the Low Tire Pressure Warning Message/Light to Display:
- The tire may have picked up a road hazard and/or have a slow leak.
- The tire pressure may not have been checked in the past six months.
- The air pressure in a cold tire may be at the pressure where the system is required to warn the driver. However, that same tire will rise in temperature and pressure as the customer drives, causing the message and light to go out.
- The tires may have been rotated, pressures adjusted, and the new tire positions were NOT re-learned into the vehicle. This can occur on vehicles that have two different placard pressures for front and rear tires.
- There may be a slow leak in one of the wheel and tire assemblies (Valve Stem, Wheel Rim, or Aluminum Wheel Porosity Leak). If this condition is found, please refer to the latest version of the following Service Bulletins:
- #05-03-10-003 – Low Tire Pressure, Leaking Cast Aluminum Wheels (Repair with Adhesive Sealant)
- #04-03-10-001 – Tire Puncture Repair Procedures for all Cars and Light Duty Trucks
The Effect of Outside Temperatures on Tire PressuresImportant: As a rule of thumb, tire pressure will change about 7 kPa (1 psi) for every 6°C (10°F) decrease in temperature – dropping when it gets colder outside, rising when it gets warmer.
Tire pressure should be set to the specified placard pressure at the lowest seasonal temperature the vehicle will encounter during operation.
The correct action to avoid a Check Tire Pressure message due to extreme temperature changes is to do the following:
- Use an accurate, high quality tire pressure gauge.
- Re-learn the TPM sensors and adjust the tire pressure to the placard values after every tire rotation.
- Let the vehicle sit and adjust the tire pressure to the specified value when the tire temperature is at the lowest expected temperature.
- Never set the tire pressure below the placard value regardless of tire temperature or ambient temperature.
Using the TPM ToolTPM Tool EL 52545
The EL 52545 TPM tool is a valuable aid in diagnosing system faults with TPM systems. It is a software-driven tool that REQUIRES periodic updates in order to work on new model cars and trucks. Failure to update the tool with the latest software version may result in possible misdiagnosis.
TPM Tool EL 52545 User Tips
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Diagnostic Tip: If you encounter a sensor that does not respond when activated by the tool, try activating another sensor that responded previously. This will help you determine if the tool is able to activate the sensor or if you have a problem with one particular sensor.
Diagnostic Tip: When using the tool during a sensor learn procedure, use the “Activate” soft key on the tool. Press the key for one second then release and the tool will perform an LF (low frequency – 125 kHz) activation cycle. You do not have to hold the key until the vehicle acknowledges. Holding the key will just reduce battery life. The LF activation of the sensors wakes them up and forces them to transmit their IDs immediately. This allows a much shorter sensor learn procedure than using the Delta P method.
TPM Frequently Asked Questions (FAQ’s)The following are some of the most asked questions:
Q: What is a Tire Pressure Monitoring System?
A: The TPM system consists of four sensors (one in each wheel), which transmit wireless (RF) signals to a vehicle receiver (typically, the same receiver that performs the keyless entry function), the Low Tire telltale, and the Driver Information Center (if equipped).
Q: Do all Vehicles Have Tire Pressure Monitoring?
A: Starting with the 2008 MY, all GM vehicles sold in the United States are equipped with tire pressure monitoring, to meet the mandates of FMVSS 138. Some vehicles built prior to the 2008 model year or sold in Canada have tire pressure monitoring; check vehicle build and RPO information to be sure.
Q: What does the Low Tire Telltale Look Like?
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Q: When does the Low Tire Telltale Come On?
A: The Low Tire telltale MUST come on when a tire's pressure drops to 75% of the Recommended Cold Inflation pressure (the pressure value printed on the vehicle placard - the yellow and white sticker in the driver door opening.)
There are several events that may cause a Low Tire warning:
- The tire may have picked up a road hazard and/or have a slow leak.
- The tire pressure may not have been checked in the past six months.
- The air pressure in a cold tire may be at the pressure where the system is required to warn the driver. However, that same tire will rise in temperature and pressure as the customer drives, causing the message and light to go out.
- On vehicles where a different placard pressure is required between the front and the rear axles, the tires may have been rotated, pressures adjusted, and the new tire positions were NOT re-learned into the vehicle.
- There may be a slow leak in one of the wheel and tire assemblies (Valve Stem, Wheel Rim, or Aluminum Wheel Porosity Leak). If this condition is found, please refer to the latest version of the following service bulletins:
- #05-03-10-003 – Low Tire Pressure, Leaking Cast Aluminum Wheels (Repair with Adhesive Sealant)
- #04-03-10-001 – Tire Puncture Repair Procedures for all Cars and Light Duty Trucks
A: The TPMS Malfunction indicator uses the same telltale as the Low Tire warning. The telltale will flash for the first 60 seconds of a KEY ON event, and then go on solid.
Q: How can I tell the difference between a Low Tire and a system malfunction?
A:
- A Low Tire telltale will be on solid immediately after KEY ON, and will be accompanied by a CHECK TIRE PRESSURE message in the Driver Information Center (if equipped).
- A system malfunction causes the telltale to flash for the first 60 seconds of a KEY ON event, and then go solid.Tip: These behaviors repeat at each KEY ON cycle. The best way to diagnose the vehicle (if you're not sure which warning is being displayed) is to KEY OFF and KEY ON again while watching the telltale and DIC messages.
A: DTC's are reported ONLY when there is a system malfunction (flashing telltale). When a Low Tire (solid telltale) is displayed, that means that the system is working exactly as it's designed to do - since there's no malfunction, there is no need for a DTC.
Q: What service is needed if the Low Tire telltale is on?
A: When a vehicle comes in with a Low Tire warning, the tires should be checked for any leaks or damage (from road hazards). After those have been repaired (or if none are found), the tires should be inflated to the pressure shown on the Vehicle Placard - the yellow and white sticker in the driver door opening. It is not necessary to relearn the sensors after correcting the pressure.
Q: Can Tire Pressure Monitoring be turned off?
A: Tire Pressure Monitoring is now a mandated safety system in the United States and cannot knowingly be disabled by an OEM nor an aftermarket service provider (49 USC 30101).
Q: Can the Tire Type and/or Placard Value be changed, if aftermarket tires or wheels are installed?
A: The Tire Type (P Metric, LT Load Range C/D/E) and the Placard Value (Front Placard and Rear Placard, individually) are stored in the receiver as calibrations and CAN be revised at a GM Dealership with a GDS2. (The RCDLR Setup screens allow this.) Since the under-inflation threshold is calculated as a percentage of the placard; correcting the placard values when different tires are installed will bring the vehicle back into compliance.
Q: What is Sensor Learning (Sensor Re-Learning, Sensor Training, Sensor Matching)?
A: Each sensor has its own unique identification code (ID) that is transmitted as part of its wireless signal. The receiver stores and uses these IDs to determine which sensors are installed on the vehicle, and in which corner of the vehicle the sensor resides in (so that both the pressure information provided in the Driver Information Center and the diagnostics are correct). Sensor Learning is the process that puts sensor ID information into the receiver.
Q: When is Sensor Learning required?
A: Sensor Learning should be done when the vehicle's tires are rotated (since sensor position on the vehicle has changed) or when a sensor is replaced/a new sensor is installed (since a new ID has been introduced to the vehicle). Sensor Learning is not required when simply correcting the tire pressure resolves the vehicle problem.
Q: Why are dashes (" - - "), or a pressure value of 148 PSI (1020 kPa), sometimes displayed after a battery disconnect?
A: These displays come up after a battery disconnect/reconnect because the system is waiting for updated pressure information to be sent from the tire pressure sensors. As each sensor transmits its information, the display is updated appropriately. Note that when dashes or 148 PSI (1020 kPa) are displayed after a battery disconnect/reconnect, the System Malfunction warning is NOT displayed - because the system is still working properly, and simply waiting for updated information from the sensors. Driving the vehicle above 20 mph (32 km/h) for 2 minutes gets the sensors talking, and restores the correct pressure values to the display. It is also possible to restore the values by using the EL 52545 TPM tool, using the "Activate" function at each tire to activate the sensor (it is NOT necessary to put the system into Learn mode, in this special case).
Q: Is there a sensor installed in the spare tire?
A: No - a sensor is not installed in the spare tire.
Q: Are all of the sensors the same?
A: All of the sensors are not the same. They are supplied by different manufacturers, and send different RF signals to the vehicle. SOME of the sensors are interchangeable, though - while they may look different, they DO send the same RF signal to the vehicle and MAY be used in place of one another on a vehicle. See the Sensor Information Guide for more details about which parts are interchangeable.
Q: What size is the sensor nut?
A: The sensor uses an 12 mm hex nut for attachment.
Q: Will a tire pressure sensor fit in every wheel?
A: GM wheels (including Accessory Wheels available from GM SPO) are designed to accommodate tire pressure sensors. Many aftermarket wheels also accommodate tire pressure sensors, but not all do. In some, the valve stem hole is placed in such a way (pointing straight into the middle of the wheel, for example) that the motion detection components inside the sensor will not work correctly.
Q: Can the valve core be replaced?
A: The valve core can and should be replaced if it is removed from the sensor. Sensors with a rubber valve stem may use a standard brass valve core for replacement. Sensors with an aluminum valve stem CANNOT use a brass core; instead, they require a nickel-plated valve core to protect against the corrosion that forms when dissimilar metals come in contact. See the service parts guide for the correct GM part numbers to order and use.
Q: Can the grommet (and washer) be replaced?
A: The grommet (and washer) can and should be replaced if the sensor is removed from the wheel. The rubber grommet provides the air seal in the valve stem opening, and a new one should be used to ensure a fresh seal after each service. See the service parts guide for the correct GM part numbers to order and use.
Q: Can the rubber valve stem be replaced by itself?
A: The rubber valve stem is attached to the sensor electronics by a TORX screw. The valve can and should be replaced whenever the sensor is removed from the wheel. See the service parts guide for the correct GM part numbers to use.
Q: Can the sensor be cleaned with a sharp pin?
A: NEVER use a sharp object to clean the pressure port of the sensor; it can be damaged and lead to part failure. If the dirt/grime/obstruction cannot be removed with a cloth, replace the sensor.
Q: How long will the sensor's battery work?
A: The sensor is designed to last for 10 years or 150,000 miles (240,000 kilometers).
Q: Are tire pressure sensors compatible with aftermarket tire sealants?
A: Tire pressure sensors are not compatible with commercially-available tire sealants. Tire sealant materials can clog the pressure port of the sensor, and lead to inaccurate pressure readings and improper Low Tire warnings. Additionally, some sealant products use materials that can degrade the protective potting material that covers the sensor's electronics.
Q: Are tire pressure sensors compatible with GM Inflator Kits?
A: While tire pressure sensors are NOT compatible with commercially-available sealants, they HAVE been tested and ARE compatible with GM Inflator Kits and the sealant that they use. After inflator kit use, the sensor should be inspected for any damage, and replaced/cleaned as needed.
Q: Are tire pressure sensors compatible with nitrogen inflation?
A: Tire pressure sensors are compatible with nitrogen inflation (normal air is already 78% nitrogen).
Q: How do changing outside temperatures affect tire pressure?
A: All gases change pressure as their temperature changes, and air or nitrogen are no exceptions. A good rule of thumb is that tire pressure will change by about 1 psi (7 kPa) when temperature changes by 10° F (6°C). Customers may experience this as temperatures change from summer to fall and into winter - tire pressures will drop as the outside temperature gets colder. Customers may also experience this as temperatures change between mid-day and overnight.
Q: How should tire pressures be set at PDI?
A: Tire pressure should be set to the specified placard pressure at the lowest seasonal temperature the vehicle will see during operation. The correct action to avoid a CHECK TIRE PRESSURE message due to extreme temperature changes is to: Use an accurate high quality tire pressure gauge. Let the vehicle sit and adjust tire pressure to the specified value when tire temperature is at the lowest expected temperature. Never set tire pressure below the placard value regardless of tire temperature or ambient temperature On extremely cold days, if setting tire pressure when the vehicle has been indoors, it may be necessary to compensate for the low external temperature by adding 3-4 psi (21-27 kPa) more than the placard pressure. When convenient, at some later time, when the tires are cold (outdoors), the pressure should be re-checked and adjusted to placard if necessary.
Q: Where should the EL 52545 tool be positioned when it is being used?
A: Tool User Tip: The placement of the TPM Tester’s antenna when activating a sensor is critical, especially with the latest software update. When activating a sensor, the antenna tip of the TPM Test EL 52545 must be placed on the sidewall, perpendicular to the tire, and close to the valve stem. This will assure proper activation of the sensor. If the antenna of the TPM Tester is placed either on the valve stem or on the wheel itself, the tool may not properly activate the sensor, causing improper diagnosis.
Warranty InformationGM is very concerned about customer safety and tire performance. Any time a customer brings a GM vehicle in for a tire or tire pressure monitoring concern, we encourage our dealers to perform a complete check of tire conditions, pressures, and the TPM system if necessary. Under normal circumstances, the condition of tires, TPM reprogramming during tire rotation, road hazard repairs, and checking/maintaining tire pressure are the responsibility of the vehicle owner. GM Dealers should encourage customers to inspect/check and maintain their tires and tire pressure on a regular monthly basis.
The tires and the tire pressure monitoring system are covered by the vehicle bumper to bumper warranty for manufacturing defects. It is GM's responsibility to perform repairs when a defect exists. If no defect exists, the customer should be responsible for the tire/system check.
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