Tire Pressure Monitoring Systems Seattle WA

Quite simply, a tire pressure monitoring system (TPMS) is an electronic system designed to monitor the air pressure in a vehicle tire and automatically transmit a warning to the driver in the event of an under- or over-inflated tire.
These systems report real-time tire-pressure information to the driver of the vehicle, either via a gamiuge, a pictogram display or a simple low-pressure warning light.

Due to the TREAD (Transportation Recall Enhancement, Accountability and Documentation) Act, all vehicles manufactured during 2008 or later are required to have a compliant TPMS system on board. The final rule requires that the driver be given a warning when tire pressure is 25% or more below the vehicle manufacturer’s recommended cold tire inflation pressure (placard pressure) for one to four tires.

While law makers and tire makers are quick to sing the praises of TPMS , as a technician or shop owner, you know that this amazing technology comes with its fair share of headaches and problems relative to diagnosis, repair and maintenance of these systems.

The following article will attempt to offer some general guidelines on making buying decisions and provide an overview of what types of products are available to make your life a little easier when working on TPMS.

Without spending too much time talking about evolving technologies, we need to cover “current state” versus ­“desired state” in terms of TPMS architecture; specifically the sensors and their power supply.

From the beginning, the prevailing design for TPMS ­sensors has included a sensor and a battery incorporated in a box inside the wheel. The designs vary from supplier to supplier, but the general concept is the same. This design describes 95-98% of the TPMS sensors in use today on passenger cars and light trucks.

The sensor inside the wheel continuously reads tire pressure and reports it back to the vehicle’s on-board diagnostic system. The system constantly compares the pressure values from all four wheels. The system also monitors and evaluates information such as vehicle speed, wheel rotation speed, ambient temperature, tire temperature and chassis height. All of this data is used to evaluate if the tire pressure is within safety margins as prescribed by the OEM and tire manufacturer.

This current design, while fairly rugged and functional, has a few drawbacks. Early on, these sensors caused problems for tire and wheel manufacturers due to clearance issues. Low-profile tires can create nightmares when mounting or demounting. Many a technician has trashed a sensor when “fishing” for the bottom bead during a demount.
Over time the sensors have gotten smaller, wheel service equipment manufacturers have developed new tools and equipment, and technicians have learned new processes to deal with TPMS sensors.

The “desired state” would be a sensor that doesn’t need a battery ...