Orlando

Tyre Pressure Monitor Description and Operation

The tyre pressure monitor system monitors the air pressure in all road tyres and provides information to the driver if any road tyre is moderately underinflated or a warning to the driver when any road tyre is significantly underinflated. The tyre pressure monitor system also provides information to the driver if any tyre is overinflated or if there is a large discrepancy between the air pressures of the left and right tyres on a given axle. By using adaptive threshold values tyre pressure monitor system can compensate for changed air pressure for various driving conditions, i.e. extra fill of air pressure for high-load, high-speed etc. The tyre pressure monitor system also allows the driver to display the individual tyre pressure and its locations on the driver information centre display. The system uses four tyre sensors, remote function receiver and the body control module (BCM). After any tyre rotation or component replacement the tyre pressure monitor system must be relearned. Refer to Tire Pressure Indicator Sensor Learn .

If all of the road wheels are without the tyre pressure sensors, e.g., winter tyres are installed, the system will recognise the change, enter into Winter Mode, and not show a malfunction.

Tyre Pressure Monitor Sensor

The tyre pressure monitor sensor, one in each wheel/tyre assembly, sends sensor ID, tyre pressure and battery low level via radio frequency communication. When the vehicle is stationary, the sensors internal accelerometer is inactive, which puts the sensors into a stationary state. In this state the sensors sample tire pressure once every 30 s and do not transmit at all if the tire pressure does not change. As vehicle speed increases to above 20 km/h (15 MPH), centrifugal force activates the sensors' internal accelerometer causing the sensors to go into rolling mode. In this mode, the sensors sample tyre pressure and temperature once every 10 s and transmit in rolling mode once every 60 s. If an 8.3 kPa (1.2 PSI) change in tyre pressure has been detected the sensor will transmit immediately.

If power is disconnected from the BCM or if the vehicle battery is disconnected each tire pressure sensor ID is retained but all of the tire pressure information is lost. Under these circumstances the BCM cannot assume that the tire pressures were maintained over an unknown period of time. If equipped, the driver information center will display all dashes and the scan tool will indicate a default tire pressure value of 1 020 kPa (148 PSI) for each tire. Driving the vehicle above 20 km/h (15 MPH) for at least 2 min. will activate the sensors causing the driver information center to display the current tire pressures.

The BCM has the ability to detect malfunctions within the tire pressure monitor system. In the event a DTC is set, the tire pressure monitor indicator icon on the instrument cluster will flash for 1 min. and then remain illuminated after the ignition is turned ON and the instrument cluster bulb check has been completed. Any malfunction detected will cause the driver information center to display a service tire monitor system type message.