RAM 1500 Owner's Manual page 558

556 STARTING AND OPERATING
If the ignition switch is cycled, this sequence will repeat,
providing the system fault still exists. If the system fault
no longer exists, the "Tire Pressure Monitoring Telltale
Light" will no longer flash, and the SERVICE TPM
SYSTEM message will no longer display, and a pressure
value will display in place of the dashes. A system fault
can occur due to any of the following:
1. Signal interference due to electronic devices or driving
next to facilities emitting the same radio frequencies as
the TPM sensors.
2. Installing aftermarket window tinting that contains
materials that may block radio wave signals.
3. Accumulation of snow or ice around the wheels or
wheel housings.
4. Using tire chains on the vehicle.
5. Using wheels/tires not equipped with TPM sensors.
The EVIC will also display a SERVICE TPM SYSTEM
message for a minimum of five seconds when a system
fault possibly related to an incorrect sensor location fault
is detected. In this case, the SERVICE TPM SYSTEM
message is then followed with a graphic display with
pressure values still shown. This indicates that the pres-
sure values are still being received from the TPM sensors
but they may not be located in the correct vehicle
position. The system still needs to be serviced as long as
the SERVICE TPM SYSTEM message is displayed.