2004 Volkswagen Phaeton Tire Pressure Monitor Lamp Diagnosis Cost

Vehicles with the added benefit of tire pressure monitoring are able to tell the driver when the air pressure in a tire is too high, too low, and, in some vehicles, what the exact tire pressure is at all times. Manufacturers use sensors in the wheels to communicate wirelessly to the tire pressure monitoring system control module, and this module will illuminate the warning light when there is a tire air pressure issue. When the light comes on, diagnosis with a scan tool is only required if the air pressure is correct at the time the warning lamp appears while driving.

The tire pressure monitoring system (TPMS) control module will receive information from the tire pressure monitoring sensors at all times the vehicle is on. In most vehicles, the only purpose of the TPMS control module is to illuminate the TPMS warning light when the tire is under or overinflated. This makes diagnosing the system very easy with the right diagnostic scan tool.

The only symptoms requiring diagnosis for the tire pressure monitoring system warning lamp is if the warning lamp has illuminated while the tires have correct air pressure, or if the air pressure for the tires is out of specification and the warning lamp is off. This is because the overwhelming majority of cases where the TPMS lamp illuminates is due to the change in ambient temperature.

The TPMS warning light comes on all the time, but that does not mean it should be ignored. The light is designed to give you fair warning of deflation before damage is done to the tire or wheel, and to prevent unsafe driving when a tire goes flat. Anytime the light comes on, pull over and check the air pressure immediately when it is safe to do so.