Tire pressure warning light is ON

[doogster]

Yesterday I drove my Smart for the 1st time in about 3 days and on the dash the little yellow tire pressure light was on.... so I drove to the Wawa near me (where they have free air machines to fill up your tires) and I was surprised to see the pressure in the front was 30 on one and 31 on the other... and on the back was 40 on one and 41 on the other... to me, that sounds right. This is the first time the warning light has come on in the 10,900 miles I have driven it... what gives here???

[Old smart]

The tire pressure monitoring system doesn't register the individual pressures, it registers a change in pressure. You can set the TPM at any pressure and not get a warning until one or more tires drops some amount below the set point. The proper cold pressures are 29psi on the front and 36psi on the rears. Once those pressures are attained, the TPM should be re-set.

Be cautious about infreqently used, free or coin-op air pumps. They are not too sophisticated, and often have water condensation in their accumulators (storage tanks) and hoses. Before filling the tire it is best to depress the center pin in the air chuck and purge any water. The tire stores' air is dry due to constant compressor usage.

[h20m0f0]

push the button on your dash and if it comes back on put air in your tires, they are probably 5 or 10lbs low