Automotive Smog Check Tips
How Can You Tell If the Vehicle Has a TPMS Sensor
If the tire/wheel assembly has a tire pressure monitoring system (TPMS)
valve type sensor, it can be usually be identified by the threaded portion
of the valve stem.
If the valve stem is black rubber, then it does not have a stem mounted
tire pressure sensor. However, the wheel may be equipped with a wheel
mounted sensor, so care should still be taken to avoid damaging the sensor
Note : The Technician shouldn't replace either the ( OEM ) / Dealership cap
or the valve stem with STANDARD PARTS. Conventional valve stem parts will
inhibit the sensors ability too transmitt it's signal.
Caution : If changing tire sizes or styles beyond the recommendations as stated
here , consult a knowledgeable tire store representative for help in matching
wheel and tire combinations to your vehicle.
Note : Some tires may be FIVE or more years of age when you purchase them.
Always look at the DATE CODE. ( DOT is the beginning of the info, date code
is the ending of that long sentence )
Shops that use Nitrogen inflation to inflate their Customers vehicles have
installed a GREEN tire valve cap over the valve stem. This lets' others know
that Nitrogen, rather than Air has been used to inflate these tires.
Automotive Principles Technology - James D. Halderman ( 1999 Edition )