How to tell which TPMS sensor is bad in Lexus?

To identify the faulty Tire Pressure Monitoring System (TPMS) sensor in a Lexus, you’ll need to read each wheel’s sensor data with a Lexus-compatible scan tool (Techstream is preferred) to see which sensor is failing, then confirm with quick checks and a relearn if you replace a sensor. The warning light alone won’t tell you which sensor is bad.

In Lexus vehicles, each wheel houses a direct TPMS sensor that broadcasts pressure (and sometimes temperature) data to the vehicle’s TPMS/ABS module. When a sensor or its battery fails, the system can light the warning or report a fault for a specific wheel. Pinpointing the exact bad sensor requires diagnostic data tied to the wheel’s sensor ID and often a formal relearn after replacement.

Understanding how TPMS works in Lexus

Lexus uses direct TPMS, with a sensor mounted in each wheel that transmits a unique ID and live data to the car’s TPMS receiver. The sensors are powered by their own batteries, so a dying battery will often trigger a malfunction code or a weak signal. Because the ID is tied to a specific wheel position, a diagnostic scan is usually needed to map which sensor corresponds to which wheel.

How to pinpoint the failing sensor

These steps combine quick checks you can do at home with more precise readings from a diagnostic tool. The home checks help you suspect a wheel, while the tool confirms the exact sensor ID and status.

• Quick checks at home:
  
  
  
  • Compare tire pressures with the recommended specification. A tire that’s consistently low or reading erratically may indicate a faulty sensor or a leak.
  
  
  • Inspect the wheel, valve stem, and sensor area for visible damage, corrosion, or a loose valve stem that could give false readings.
  
  
  • Note whether the TPMS warning behaves differently with temperature or road conditions; a sensor with a weak battery may behave inconsistently.
  
  
  • If you have access to a TPMS tool, attempt a sensor “activation” test to see which sensor IDs respond and which do not.
  
  
  • Swap front-to-back or left-to-right positions after recording each wheel’s readings to see if a fault follows a particular sensor or stays with the wheel position. The test helps isolate the defective unit when combined with data from a scan tool.
  
  
  
  

These home checks help you narrow down the suspect wheel, but they cannot conclusively identify the bad sensor without diagnostic data from a scan tool.

Diagnostic steps with Techstream or a compatible TPMS tool

Using Techstream or a capable handheld TPMS tool lets you read the exact sensor IDs, status, and health alarms for each wheel. This is the most reliable way to determine which sensor is failing and whether the issue is a sensor, battery, or communication problem.

• Connect the scan tool to the vehicle and navigate to the TPMS section. Retrieve the per-wheel sensor IDs and their current status (OK, Not Communicating, Low Battery, etc.).


• Review live data for each wheel, including reported tire pressure, sensor temperature, and battery voltage. A sensor showing “Low Battery” or “No Communication” is a strong candidate for the bad unit.


• Check the sensor ID-to-wheel mapping. If the ID reported by the tool matches the wheel you’re testing, you can confirm the fault location. If you rotate tires, re-check after relearning to verify whether the fault follows the sensor or stays with a wheel position.


• Perform a TPMS relearn/rebind procedure if you replace a sensor. This associates the new sensor IDs with wheel positions so the system correctly tracks each wheel going forward. Some Lexuses require Techstream or a compatible tool to complete the relearn; others may support an automatic relearn after a brief test drive.

In summary, the diagnostic data from Techstream or a capable TPMS tool (sensor IDs, status, battery health) provides a definitive answer about which sensor is bad. A visual and pressure check complements the data to ensure there isn’t another nearby issue.

Replacing a bad TPMS sensor and relearn procedure

If you confirm a bad TPMS sensor, you’ll typically replace the sensor (and sometimes the valve stem) and then relearn the system to assign the new sensor to the correct wheel position.

1. Purchase the correct sensor: direct TPMS sensor compatible with your Lexus model year, with the correct frequency (usually 315 MHz or 433 MHz, depending on the market) and, if possible, a matching valve stem.


2. Remove the tire from the rim and replace the faulty sensor (and valve stem if needed). Ensure the sensor is properly seated and the tire is free of debris before remounting.


3. Balance the wheel and reinstall the tire. Inflate to the recommended pressure and check for leaks.


4. Relearn or rebind the sensor IDs to wheel positions using Techstream or a compatible TPMS tool. If your model supports an automatic relearn, you may be instructed to drive at a certain speed for a set duration; otherwise, follow the tool’s prompts to complete the relearn.

After replacement and relearn, drive the vehicle as directed by your tool or owner’s manual to let the system calibrate. If the light stays on or returns after a few tests, have the system rechecked for leaks, loose connections, or a faulty sensor again.

Professional vs. DIY considerations

DIY TPMS work is feasible for confident owners with the right tools, particularly for sensor activation tests and basic relearnings. However, the most reliable identification and relearn typically require Techstream or a professional-grade TPMS tool. If you’re unsure, a dealer or tire shop can perform a precise diagnosis, confirm sensor IDs, and complete the relearn and balancing with OEM parts.

What to do if you don’t have the tools

If you don’t have access to Techstream or a capable TPMS tool, your best option is to visit a tire center or Lexus service facility. They can read the exact sensor IDs, confirm the failing unit, perform the relearn, and ensure the tires are balanced and inspected for valve issues or leaks.

Summary

Pinpointing a bad TPMS sensor in a Lexus hinges on confirming the faulty wheel through a combination of live per-wheel data and a sensor ID map. A Lexus-compatible scan tool (Techstream) is the most reliable method to identify which sensor is failing by showing each wheel’s sensor status and ID. Visual checks, pressure readings, and a controlled sensor swap can support the diagnostic, while a proper relearn after replacement ensures the system tracks the correct wheel positions going forward. For best results, use the Techstream approach or visit a professional shop to avoid misdiagnosis and ensure safe, accurate TPMS operation.

How to tell which TPMS sensor is bad on a Toyota?

You can tell which TPMS sensor is bad on a Toyota by using a TPMS diagnostic tool to communicate with each sensor and see which one is not responding or is showing an error, or by using an OBD2 scanner that can read live TPMS data, which may show a sensor is sending a false low-pressure reading. A tire shop can also perform this diagnosis for you using their specialized tools. 
You can watch this video to see how a TPMS tool is used to find a bad sensor: 59sAuto Repair GuysYouTube · Jun 15, 2022
Method 1: Use a TPMS diagnostic tool 

• This is the most direct method and is performed by a tire shop or a professional mechanic. 
• The tool is held near each tire's valve stem to communicate with the sensor. 
• The tool will show information like tire pressure, sensor ID, and battery status for each wheel. 
• A sensor is likely bad if the tool cannot connect to it, if the pressure reading is incorrect, or if it fails to "wake up" when triggered. 
• Some tools can also be used to put the car into a "program mode," and the one that doesn't beep or respond is the faulty one. 

Method 2: Use an OBD2 scanner 

• Connect the scanner to the vehicle's OBD2 port.
• Access the live data stream for the TPMS system.
• The scanner will display the pressure reading from each sensor.
• A bad sensor will often show a pressure of zero or an incorrect value while the tire is properly inflated.
• The scanner may also provide a specific trouble code (like C1503) that indicates which sensor is at fault. 

This video demonstrates how to use an OBD2 scanner to identify a bad TPMS sensor: 51sBudget MechanicYouTube · Mar 22, 2025
Method 3: Take it to a professional

• A tire shop has the necessary specialized tools to diagnose TPMS issues.
• They can accurately identify the faulty sensor and replace it for you.
• Many shops can perform the diagnosis and replacement for a reasonable price. 

How long do Lexus TPMS sensors last?

5-10 years
Most TPMS sensors run on batteries that are built into the sensor and these batteries are not replaceable. The life expectancy of the lithium ion batteries in a TPMS sensor is anywhere from 5-10 years.

Does Lexus tell you which tire is low?

Yes, many modern Lexus models with the Tire Pressure Monitoring System (TPMS) will tell you which tire is low. You can see individual tire pressures on the multi-information display on your dashboard by using the steering wheel controls to scroll through the information. However, some older models may only show a general warning light without specifying the location. 
How to find the low tire information

• Use the steering wheel controls: On newer models, you can navigate to the tire pressure display on your driver's display by using the scroll buttons on your steering wheel. 
• Look for the pressure readouts: Once you find the correct screen, you should see the pressure for each tire listed numerically, allowing you to easily identify which one is low. 
• Check the infotainment system: Some Lexus models may also have a status or vehicle information section within the infotainment or companion app that displays the individual tire pressures. 

What to do when the light comes on

• Stop and check: If the TPMS light comes on, stop the vehicle in a safe place and inspect your tires for damage or low pressure. 
• Inflate the tire: Add air to the low tire until it reaches the manufacturer's recommended PSI, which can be found on a sticker inside the driver's side door jamb or in your owner's manual. 
• Reset the system: After inflating the tires, you will need to reset the TPMS system. This is typically done by driving the vehicle for a short period or following a specific reset procedure, which can also be found in your owner's manual. 

How to identify a faulty TPMS sensor?

Sensor Malfunctions: If your tire pressure is within the recommended range, but the sensor triggers a warning light, it may be malfunctioning. Handling Differences: Should you notice handling changes like swerving or flat tires without a TPMS alert, the sensor might be failing to detect these crucial pressure drops.