Tire Pressure Monitoring (TPM) System

TIRE PRESSURE MONITORING (TPM)

DESCRIPTION

General
The Tire Pressure Monitoring (TPM) system continuously monitors tire pressures so long as vehicle battery power is available. If a low tire pressure is detected, the system alerts the driver via the message center when the ignition is on. The system monitors the tire pressure of each road wheel and the full size spare wheel.

NOTE: The tire pressure of a space saver spare wheel is not monitored.

OPERATION

Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fuse 16 and fuse 53 of the passenger compartment fuse box (C0632) on an R wire. Fuse 16 (C0586) provides a constant battery feed to the TPM ECU (C1537) on an RNY wire. The TPM ECU (C1537) is located under the front passenger seat and is earthed on an NB wire.

Fuse 53 (C0583) provides a constant battery feed to the ignition switch (C0028 on V8 vehicles) on an R wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028 on V8 vehicles) to fuse 6 of the passenger compartment fuse box (C0585) on a G wire. Fuse 6 (C0587) provides an ignition feed to the TPM ECU (C1537) on a GN wire.

TPM Antennae
An air pressure and temperature sensor is fitted to the rim of each road wheel and the full size spare wheel. The sensors transmit radio signals to the relevant antenna at a frequency of 433 MHz. The TPM ECU (C1537) is connected to the antennae as follows:

- To the RH front TPM antenna (C2027) by a W and a U wire
- To the LH front TPM antenna (C2026) by a W and a G wire
- To the RH rear TPM antenna (C2029) by a W and a Y wire
- To the LH rear TPM antenna (C2028) by a W and an R wire.

TPM Reset Switch
The TPM ECU (C1537) provides a feed to the TPM reset switch (C0700) on a UR wire. When the switch is pressed, a feed is returned to the TPM ECU (C1537) on a UN wire. When the TPM registers that the reset switch has been pressed, it takes the current tire pressure readings as the nominal pressures.