Jeep 2009 Grand Cherokee - Owner Manual - Manual (Page 350)

A tire pressure monitoring sensor is located in the spare
wheel, if the vehicle is equipped with a matching full-size
spare wheel and tire assembly. The matching full-size
spare tire can be used in place of any of the four road
tires. A low spare tire will not cause the Tire Pressure
Monitoring Telltale Light to illuminate, a warning mes-
sage to appear, or the chime to sound.
The Tire Pressure Monitoring Telltale Light will
illuminate in the instrument cluster, a “TIRE LOW
PRESSURE” message will display in the instru-
ment cluster for 60 seconds, and an audible chime will be
activated, when one or more of the four active road tire
pressures are low. Should this occur, you should stop as
soon as possible, check the inflation pressure of each tire
on your vehicle, and inflate each tire to the vehicle’s
recommended cold placard pressure value. The system
will automatically update and the Tire Pressure Monitor-
ing Telltale Light will extinguish, once the updated tire
pressures have been received. The vehicle may need to be
driven for up to 20 minutes above 15 mph (24 km/h) to
receive this information.
The Tire Pressure Monitoring Telltale Light will flash on
and off for 75 seconds, and remain on solid when a
system fault is detected. In addition, a “CHECK TPM
SYSTEM” message will be displayed for 75 seconds when
a system fault is detected, and a chime will sound. If the
ignition key is cycled, this sequence will repeat, provid-
ing the system fault still exists. The Tire Pressure Moni-
toring Telltale Light will turn off when the fault condition
no longer exists. A system fault can occur by any of the
following:
1. Jamming due to electronic devices or driving next to
facilities emitting the same Radio Frequencies as the TPM
sensors.
2. Installing some form of aftermarket window tinting
that affects radio wave signals.
348 STARTING AND OPERATING