TPMSSensor

Tire Pressure Monitoring Sensor (TPMS)

Group: Chassis and safety

The TPMS warns you when one or more tires are low on pressure. It can be direct, with a sensor inside each wheel, or indirect, calculated from the ABS sensors.

Contents

What does the TPMS sensor do?

In a direct system, each wheel has a battery-powered sensor mounted on the valve stem that measures pressure and temperature and transmits them by radio (315 or 433 MHz) to the vehicle. In an indirect system, the vehicle detects that one wheel turns faster than the others (an underinflated tire has a smaller diameter). The direct system shows the pressure of each tire; the indirect one only warns of a difference.

Where is it located?

Direct: inside the rim, attached to the valve stem. Indirect: it has no sensors of its own; it uses the ABS sensors.

Signal type and reference values

  • Radio transmission with a unique ID for each sensor.
  • Built-in battery lasting roughly 5 to 10 years, not replaceable on most sensors.
  • Typical warning when pressure drops 20 to 25% below the recommended value.

Values are a guide only: always check the manufacturer's data for your vehicle.

Symptoms of a bad TPMS sensor

  • Steady tire pressure light: real low pressure.
  • Light flashing for a few seconds and then staying on: a failed sensor or a system fault.
  • One wheel shows "--" on the dashboard.

How to test the TPMS sensor step by step

  1. Measure the pressure of all four tires (and the spare, if it has a sensor) with a gauge and set it cold.
  2. Run the reset or relearn procedure described in the owner's manual.
  3. With a TPMS activation tool, read each sensor: ID, pressure, temperature and battery status.
  4. If you changed wheels or rotated the tires, the sensors must be relearned to their positions.

Trouble codes related to the TPMS sensor

Frequently asked questions about the TPMS sensor

Can a TPMS sensor battery be replaced?
On most sensors, no: the battery is sealed in and the whole sensor is replaced.
Why does the light come on when it gets cold?
Because pressure drops about 0.1 bar (1 to 2 psi) for every 10 °C (18 °F). The light often comes on the first cold morning even without a puncture.

Updated September 25, 2026. Values are a guide only: always confirm them in the service manual for your engine.

Other sensors