Ambient Temperature Change and Tire Pressure
Tire pressures fluctuate with temperature changes. For this reason, tire pressures must be set to specification when tires are at outdoor ambient temperatures. If the vehicle or trailer is allowed to warm up to shop temperatures, and the outside temperature is less than shop temperature, the tire inflation pressure must be adjusted accordingly.
If the tires are inflated to specification at shop temperatures, and the vehicle or trailer is moved outdoors when the outdoor ambient temperature is significantly lower, the tire pressure may drop enough to be detected by the TPMS and illuminate the TPMS warning indicator or display a TPMS fault message in the message center.
Tire pressure decreases by 6.9 kPa (1 psi) for every drop of -12.2 °C (10 °F) of outside ambient temperature. Similarly, as the ambient temperature decreases by a delta of 5.6 °C (42 °F), tire pressure decreases by 6.9 kPa (1 psi). Adjust the tire pressure by 6.9 kPa (1 psi) per -12.2 °C (10 °F) (6.9 kPa [1 psi] per 5.6 °C [42 °F] delta) of outside ambient temperature change as necessary to keep the tire at the specified VC label pressure. To adjust the tire pressure indoors for colder outside temperatures, refer to the following chart.