Description And Operation
DESCRIPTION
The Tire Pressure Monitoring (TPM) system is made up of the following:
| 1. | Refer to TIRE PRESSURE SENSOR . |
| 2. | Refer to TIRE PRESSURE MONITOR (TPM) . |
| - | Refer to INSTRUMENT PANEL CLUSTER (IPC) . |
OPERATION
Vehicles can be equipped with a Base or a Premium TPM System.
The system monitors the pressure of each tire and warns the driver, when either a low tire pressure conditions or a TPM system malfunctions exists, through the IPC.
The Base TPM system only uses the TPM telltale, which is an audible chime and non-positional text messages to indicate low pressure or system fault conditions.
The Premium TPM system uses the base system TPM telltale audible chime and the vehicle information display to display the actual tire pressure values or dashes for each of the four active road tires in the correct vehicle position. Various text messages, as required, shall also be displayed in the vehicle information display.
This system consists of the following components: one TPM, four or five TPM sensors.
The TPM receives the radio signals from the tire pressure sensors and sends the relevant values to the other modules via Controller Area Network - Chassis (CAN-C). The TPM identifies the sensor position, receives the sensor data, compares the pressure data with the standard pressure values stored in the non-volatile memory, determines whether there is a problem in the tire pressure and stores the warnings regarding tire pressure and system faults. The TPM used the Radio Frequency (RF) Data from the TPM sensor and the wheel speed data to determine the location of each tire pressure sensor. When a sensor is installed in a tire on the vehicle, the TPM can automatically identify the sensor and its location during the first ensuing drive cycle. Identification (ID) will take approximately 20 minutes but the speed of the vehicle must exceed 24 km/h (15 mph). The TPM/RKE ANALYZER 2046300080 can be used to program the new sensor ID number in the TPM. The sensor IDs can also be programmed using a diagnostic scan tool to scan each TPM sensor at each road wheel, and store each sensor ID in the correct location.
| Refer to COMPONENT INDEX . |
The IPC for this vehicle is located in the instrument panel above the steering column opening. The IPC gauges and indicators are visible through an opening in the cluster bezel and are protected by a clear plastic cluster lens that is secured to the cluster housing by integral latch formations. Several versions of the IPC are offered on this vehicle. These versions accommodate all of the variations of optional equipment and regulatory requirements for the various markets in which the vehicle is offered. The IPC utilizes integrated circuitry and information carried on the CAN data buses and CAN-Interior High Speed (IHS) along with several hard wired inputs to monitor other sensors and switches in the vehicle. In response to those inputs, the internal circuitry and programming of the IPC allow it to monitor many electronic functions and features of the vehicle. The IPC receives and manages the messages coming from the compass module and the humidity sensor (if present) via the Local Interface Network (LIN) data bus.
The IPC performs the following functions:
- Receives TPM A1 message from TPM module
- Process the information received from the TPM module
- Gives warning to the driver through a dedicated lamp, text messages and chime activation
- Manages the TPM indicator lamp function, text message and chime activation function for a loss of CAN communication
The IPC provides the following:
INPUTS
- Tire pressure indication requests from TPM
- Chime request from TPM
- TPM warning request to IPC
- TPM error request to IPC
OUTPUTS
- Odometer reading to TPM
| Refer to COMPONENT INDEX . |
The TPM is a module that is able to receive tire pressure, temperature, sensor ID and function code data via RF data transmitted from the sensors inside the wheel. The TPM stores all warning and fault conditions, placard pressure values, low pressure threshold values, all wheel sensor IDs and locations, and faults in memory that can be accessed through diagnostic communication. The TPM software is able to be re-flashed over the CAN bus through use of a diagnostic scan tool connected to the vehicle's diagnostic connector. The TPM controls the TPM indicator lamp function including conducting a bulb check operation at every ignition ON key cycle.
The unit has a CAN-C interface to connect it to the network and performs the following functions:
- Receives and processes RF signals from each TPM sensor
- Monitors TPM sensor status
- Manages internal power
- Performs self-test
- Implements algorithms and logic to generate low pressure and system malfunction warnings
- Transmits data from/to other modules on CAN-C
- Performs diagnostic functions via CAN bus
The TPM receives the following:
CAN-C INPUTS
- VSS signal supplied from the Anti-lock Brake System (ABS) Module
- Vehicle configuration supplied from Body Control Module (BCM)
- Ignition state supplied from BCM
- Averaged ambient temperature supplied from BCM
- Battery voltage input from BCM
- Current gear supplied by BCM
- Ambient air pressure (barometric pressure) supplied from Powertrain Control Module (PCM)
- Vehicle Identification Number (VIN) data and VIN message from PCM
- Odometer reading from IPC
The TPM provides the following:
CAN-C OUTPUTS
- Tire pressure indication requests to IPC
- TPM chime request to IPC
- TPM warning request to IPC
- TPM error request to IPC
The TPM receives the following:
RF INPUTS
- Left Front TPM Sensor
- Left Rear TPM Sensor
- Right Front TPM Sensor
- Right Rear TPM Sensor
- Spare Tire TPM Sensor (if equipped)
| Refer to COMPONENT INDEX . |
One tire pressure sensor is mounted to a valve stem specifically designed for mounting the pressure sensor in each wheel in place of the traditional tire valve stem. Each sensor has an internal battery that lasts up to 10 years. The battery is not serviceable. At the time of battery failure, the sensor must be replaced. The TPM sensor operates on a 433 MHz radio frequency. The tire pressure sensor valve stem looks similar to a standard valve stem with the tire mounted on the wheel. To visually identify a tire pressure sensor/valve stem, the valve stem cap is longer than a standard valve stem. This vehicle uses the 433 MHz TPM sensor. Although 315 MHz and 433 MHz sensors are identical in size and shape, they are not interchangeable. Always make sure the correct sensor is being used. A TPM/RKE ANALYZER 2046300080 can be used to determine the sensor's frequency without having to dismount the tire.
The battery operated tire pressure sensor is both a transmitter and a receiver. The TPM sensor can be forced to transmit if using a special tool such as a TPM/RKE ANALYZER 2046300080 Analyzer. The TPM/RKE ANALYZER 2046300080 Analyzer has the ability to change the sensor mode and to diagnose a faulty TPM sensor. Using a TPM/RKE ANALYZER 2046300080 Analyzer can take up to a minute to force a transmission from a sensor. Each sensor's (transmitter) broadcast is uniquely coded so that the module can monitor the state of each of the sensors on the four rotating road wheels. The module can automatically learn and store the sensor's ID while driving "within 10 minutes continuously above 24 km/h (15 mph)" after a sensor has been replaced. The vehicle must be stationary for more then 20 minutes in order to initiate the learning sequence. The sensor IDs can also be programmed using the TPM/RKE ANALYZER 2046300080 Analyzer Tool. Scan each TPM sensor at each road wheel, and store each Sensor ID in the correct location. (LEFT FRONT, LEFT REAR, RIGHT FRONT, and RIGHT REAR) Connect the TPM/RKE ANALYZER 2046300080 Analyzer Tool to the scan tool. Then follow the programming steps outlined in the diagnostic scan tool for "Program Tire Pressure Sensor ID w/ TPM Tool".
The TPM sensor provides the following:
RF OUTPUTS
- Left Front TPM Sensor
- Left Rear TPM Sensor
- Right Front TPM Sensor
- Right Rear TPM Sensor
- Spare Tire TPM Sensor (if equipped)