Dodge ZB 2005 Service Manual page 1399

GENERAL INFORMATION
The TPM module retains its own ID number, each
of the four transmitter ID numbers, module ver-
sion, date of manufacture, and low/critical thresh-
olds.
NOTE: Tire pressure
replacement involves removal of the tire from
the wheel. Service procedures can be found
in Section 2 of the service manual.
Tire Pressure Sensor/Transmitter
The system has four individual Tire Pressure
Sensor/Transmitters, one mounted in each wheel.
The valve stem is integral with the pressure sensor/
transmitter. Each tire pressure Sensor/transmitter
serves three functions:
1. Valve stem to inflate and deflate the tire
2. Measures tire pressure.
3. Transmits the tire pressure value to the TPM
Module.
The Tire Pressure Sensor/Transmitter unit consists
of:
– Three-volt battery
– Pressure sensor
– Roll switch (speed activated)
– Reed switch (magnet activated)
– Transponder coil (125 kHz activated)
– Radio Frequency (RF) transmitter.
CAUTION: Inflatable tire sealant for fixing a
slow leak or flat tire should be avoided, as
the sealant will clog the pressure-sensing
hole in the transmitter.
Battery
The three-volt Lithium battery is used to enable
the Tire Pressure/Sensor Transmitter unit. The
battery is only used above 33 kph (20 mph) to
extend service life. The transmitters notify the TPM
module when its battery condition is low. Upon
receiving a low battery message, the TPM module
will track the status of the battery for 3 consecutive
ignition cycles. (An ignition cycle is defined as:
ignition on, and left on for at least 15 minutes, and
vehicle speed above 33 km/h (20 mph) long enough
for the TPM module to receive a transmission from
each transmitter.) If the battery condition is still
low after 3 consecutive ignition cycles, the TPM
module will set a Diagnostic Trouble Code (DTC.)
The battery is a non-serviceable part and must be
replaced with a complete Tire Pressure Sensor/
Transmitter unit and reprogrammed using the
DRBIII .
sensor/transmitter
18
Roll Switch
There is an integral roll switch within the Tire
Pressure/Sensor Transmitter that must be closed
before the transmitter is enabled. This roll switch is
open when the vehicle is stopped or below 33 km/h
(20 mph.) When the vehicle is moving above 33
km/h (20 mph) centrifugal force will close the roll
switch.
NOTE: The transmitter will continue to
transmit for 15 minutes and once an hour
after the roll switch has opened. If a
transmitter is tested with Miller tool 9001, and
it is determined that a RF signal is present,
the vehicle must driven to verify roll switch
closure.
Transmitter
The measured tire pressure value is transmitted
when the vehicle speed is above 33 km/h (20 mph),
every 60-68 seconds or if the pressure drops 6.9 kpa
(1 psi) or more between sampling periods. It is
important to note that not all the tire pressure
sensor/transmitters will start to transmit at the
same time. Due to manufacturing tolerances some
transmitters may start to operate with speeds as
low as 16 Km/h (10 mph.)
The TPM module continuously monitors and
records the last 32 transmissions that it receives.
When the TPM module notices that one of the Tire
Pressure Sensor/Transmitters has not sent its in-
formation within the last 32 transmissions, it will
set a Diagnostic Trouble Code (DTC) and request
the ''Lo Tire'' LCD message on. If the transmitter
begins transmitting again, the module will shut off
the ''Lo Tire'' LCD message, however, the transmit-
ter ID and number of occurrences are stored. This
data is in the TPM module memory and can be
erased using the DRBIII . If this type of failure
occurred, the BCM DTC will have to be cleared as
well.
Reed Switch
A magnet is used to close the reed switch. The
only time that the reed switch is used is when the
TPM module is reprogrammed. When a magnet is
placed over the end of the valve stem for six
seconds, it will close the reed switch. With the reed
switch closed the transmitter will send its ID and
tire pressure to the module. The ID and tire pres-
sure can be read using the DRBIII .
Transponder Coil
A transponder coil is packaged in the transmitter,
which can also be used to reprogram the TPM. This
is achieved by using a low frequency activation/
receiver device designed for 125kHz to activate the
transmitter electromagnetically. The activation/
receiver device can also be used for read back of the