Description & Operation

The Tire Pressure Monitoring (TPM) system monitors air pressure in the four road tires (excludes spare). Pressure in the spare tire is monitored incase of a matching spare with sensor. Sensor transmissions occur if there is a significant change in pressure. Radio Frequency Hub Module (RFHM) has to be awake when sensor transmits to monitor spare pressure. The TPM system consists of tire pressure monitoring sensors attached to each road wheel through the valve stem mounting hole, an electronic display, and an indicator lamp. The system communicates through the (RFHM). Upon detection of a warning or fault condition, the RF Hub will send a request to the module that controls the indicator lamp and the text display via the vehicle bus system to illuminate or flash the indicator lamp. Also, upon detection of a warning or fault condition, the electronic display will send a request to sound the "chime". |

The RF Hub will store all wheel sensor IDs and locations and faults in memory that can be accessed through diagnostic communication. All other data values transmitted from each active wheel sensor shall be stored in the RF Hub memory. The RF Hub automatically learns and stores the sensor IDs while driving "within 20 minutes continuously above 20 mph (32 km/h)" after a sensor has been replaced. The learning sequence will initiate when the vehicle has been stopped for more than 20 minutes.

NOTE: A new sensor ID can also be programmed directly into the RF Hub by using a RKE-TPM Analyzer in conjunction with a Scan Tool. Once the new sensor ID has been programmed, the RKE-TPM Analyzer can be used to update the TPM System by activating the sensor.

If the TPM system detects that the tire pressure in any road tire is low, beyond the Low Pressure (lamp) ON threshold (see placard table below), the TPM system will continuously illuminate an indicator lamp. If a system fault is detected, the indicator lamp will flash on/off for 75 seconds, then remain on solid. If the RF Hub detects a warning or fault condition at ignition key "on", the display module will request a chime once per ignition cycle for the first "warning" or "fault" condition detected. A "warning" or "fault" condition will remain enabled until the problem causing the condition is corrected and removed/reset.

If a system fault is detected, a chime will sound, and the TPM indicator (telltale) lamp will flash for 75 seconds, then remain on solid. For vehicles with the Premium TPM Systems, a "CHECK TPM SYSTEM" message will appear in the Electronic Vehicle Information Center (EVIC), followed by a graphic display. A system fault can occur by many scenarios, including the following:

Signal interference due to electronic devices or driving next to facilities emitting the same Radio Frequencies as the TPM sensors.
Installing some form of aftermarket window tinting that affects radio wave signals.
Accumulation of snow or ice around the wheels or wheel housings.
Using tire chains on the vehicle.
Using wheels not equipped with TPM sensors.