Your Nissan Frontier is equipped with a Tire Pressure Monitoring System (TPMS). When the system detects the tire pressure is low, a light will illuminate on your dashboard. This light serves as a reminder to check your tire inflation level. It will not reset or turn off until the system detects that the tires are inflated to their recommended levels.
The proper inflation levels will depend on your model-year and tire size, but this information can be found on your Frontier.
Examine your driver-side door jamb (with the door open) to find your Frontier's tire inflation label. The exact specification will depend on which model-year and tire size you have, but it will be listed on the label.
Note the inflation recommendation for all four tires--it's often different for the rear tires.
Drive your Frontier to a service station with an air machine. If you have an air compressor, feel free to use it instead.
Unscrew the valve stem caps on your tires. Attach the tire gauge to the stems to view the current inflation level.
Add air in small increments. Check the inflation level again, after each increment. Continue this until the tire reaches its recommended level. Repeat the procedure for all four tires.
Replace all four valve stem caps and tighten them by hand.
Drive your Frontier around the block a few times, at a speed of at least 16 miles per hour. At lower speeds, the tire pressure monitoring system does not recheck the inflation levels. After driving around a bit, your tire pressure monitor will recheck the inflation level. If the tires are properly inflated, the system will reset and turn off, according to the Frontier's manual.
