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How To Diagnose And Fix TPMS Under 30 Mins


How To Diagnose And Fix TPMS Under 30 Mins

Is the TPMS light on after filling the air? Or is the tire pressure reading on the dashboard incorrect? This can be due to a malfunctioning component within the TPMS system. It is common practice to replace the TPMS sensor and call it a job done, but the sensor is not always bad, which necessitates that you inspect the system correctly to determine the actual cause to completely eliminate the issue. We all know the importance of correct tire pressure, so it is important that you carry out a diagnosis of the system before replacing the parts willy nilly.



TPMS Diagnosis

The tire pressure monitoring system (TPMS) serves the simple purpose of making the driver aware of the tire pressures of the vehicle. Under normal conditions, if the PSI reading falls below 25% of the recommended value, the tire sensor sends a radio frequency to the ECU that determines if the pressure is below the threshold and alerts the driver, indicating a TPMS symbol on the console. However, there are several reasons that a TPMS light will come on the dashboard, including depleted sensor batteries, improper relearning after tire rotation, etc.


Furthermore, the number of misconceptions and misunderstandings that surround the working, vehicle-specific procedures and inspection of the TPMS system calls for a correct diagnosis of the system. It not only helps in eradicating the errors but also verifies that each sensor is in perfect condition and gets you acquainted with how some of these systems operate.


Step 1. Know The Difference Between A Solid And A Flashing Light

A. Solid Light: Low Tire Pressure

  • If the warning light remains illuminated, the TPMS system shows that one or more tires have been inflated to 25% less than the recommended pressure.
  • Check the placard on the vehicle for the recommended tire pressure and fill up the tire accordingly to ensure the TPMS warning light goes away.
  • Some TPMS systems also read the spare tire pressure, so it is important to check the proper pressure in the spare tire in order to ensure the TPMS light stays off.


B. Flashing Light (Malfunction Indicator Light, MIL)

  • If the warning light flashes for 60 to 90 seconds and then stays lit, there is a fault in the TPMS system, module, or sensor.
  • Check the sensor body and stem for bends or visual damage, which can cause it to malfunction and can be fixed by replacing the sensor.
  • If you see no damage and everything looks fine, carry out a quick “Test Before Touch” procedure using a TPMS tool to check the response from each tire pressure sensor.

Step 2. Test The Tire Pressure Sensors Using A TPMS Tool (Approx 15 Minutes)

  • Grab a TPMS testing tool that will help you activate and test the response signal from each tire pressure sensor.
  • Turn on the TPMS tool and select the manufacturer, model, and year of the vehicle.
  • Aim the TPMS tool towards the valve stem and trigger the tire pressure sensor on one wheel. The tire pressure reading will be displayed on the TPMS tool.
  • Compare the pressure value displayed on your TPMS tool with a tire pressure gauge. A properly functioning sensor would relay a correct tire pressure value, which would match the reading on the gauge.
  • Repeat the procedure and trigger the sensors of all four wheels with the help of the TPMS tool and take the readings. A mismatching reading indicates a faulty sensor and replacing the same should fix the issue.
  • If the TPMS tool shows "no sensor detected" or reads no value for any of the wheels, the tire pressure sensor of that wheel is faulty.
  • Generally, if a tire pressure sensor goes bad, it's likely that others might fail soon. The batteries on these sensors have a finite lifespan and one can choose to replace all the sensors at once.
  • If all the wheel sensors work perfectly and the console still shows as a TPMS warning light, a relearn is required. If the sensor is functioning properly but programmed to the wrong make and model of the vehicle or it was never relearned, the ECU might not be reading the sensor, causing the TPMS light to illuminate.


Step 3. Relearn The TPMS System (Approx 30 Minutes)

TPMS relearn procedures may vary depending on the manufacturer and one must know which relearn procedure is required. According to Automotive Maintenance & Repair Association (AMRA), 38% of Asian, Domestic, and European vehicles use Auto relearn procedure, 27% use OBD, and 35% use Stationary relearn procedures with modern vehicles switching more towards OBC relearn procedures. Advanced TPMS tools are compatible with a wide selection of vehicles and have excellent OBD coverage to keep up with the growing industry of TPMS, offering a correct and easy relearn for your vehicle.


A. Automatic Relearn Procedure

  • First, inflate all the tires to the recommended pressures listed on the vehicle’s placard.
  • Turn the ignition on and grab your TPMS tool.
  • Select the vehicle, make, model, year, on the TPMS tool and scan each wheel sensor by aiming the tool towards the valve stem and triggering the tire pressure sensor.
  • The tool will display the order in which you have to trigger the wheel sensor, which is usually: left front, right front, right rear, and left rear tire.
  • After scanning each sensor, drive the vehicle above 15mph for at least 20 minutes and all the sensor IDs will be memorized automatically, completing the relearn procedure.


B. OBD Relearn Procedure

  • Inflate the tires and select the vehicle’s make and model, just like the steps mentioned above.
  • Grab your TPMS tool and select the option relearn mode on the TPMS tool menu.
  • Trigger each wheel sensor in the order left front, right front, right rear, and left rear.
  • Once all the sensors are triggered, connect the TPMS tool to the OBD II diagnostic port in your vehicle.
  • Turn on the ignition and wait until all the sensor IDs are written into the TPMS ECU and the tool displays the message: OBD Relearn Successful.
  • Disconnect the tool from the OBD port and turn the ignition off and on again, and start the vehicle to see the TPMS warning light is gone. 
  • Sometimes you'll need to drive your car for a few minutes for the warning light to go away permanently.

 

C. Stationary Relearn Procedure

  • Turn the ignition on and press the lock and unlock buttons at the same time on the keyless entry fob to hear the horn sound twice. This indicates that the TPMS receiver is in the learn mode.
  • Hold the TPMS tool aimed at the sensor, starting with the left front wheel. Trigger the sensor to hear the horn beep once.
  • Trigger all the sensors in the same order, i.e. left front, right front, right rear, and left rear wheel. In some cars, the turn signal of that particular side will light up for the side of the wheel you have to read the sensor.
  • Each horn sound indicates the confirmation that the tire pressure sensor ID has been learned.
  • Initiating a stationary relearn procedure can differ by the vehicle manufacturer and may require a specific sequence, which may include turning a key a few times, holding the brakes, and other combinations. Most vehicles use the keyless-entry fob transmitter’s LOCK and UNLOCK buttons.

 

TPMS diagnostic tools are very handy, and they allow you to take a step-by-step approach in carrying out a thorough inspection of your TPMS system. A proper diagnosis helps you to know potential issues with the system which can be taken care of before you hit the road. This helps in maintaining optimum tire pressures which improve your vehicle's handling and performance. Also, after performing a complete TPMS diagnostic procedure yourself, it becomes easier for you to relearn and program the tire pressure sensors while replacing tires during winters and summers. Advanced TPMS tools come with easy, less complicated, and step-by-step instructions specifically for your vehicle's make and model to diagnose and relearn your TPMS system easily.

John Framigllia
Technical Writer
Our technical writer is known for simplifying automotive parts and services. Intuitive with various vehicles and manufacturers, he knows how to simplify complicated problems.