TPMS System Description
Overview
The TPMS (Tire Pressure Monitoring System) continuously monitors all four tire pressure sensors and the system function whenever the vehicle is turned to the ON mode. If it detects low pressure in a tire, it alerts the driver by turning on the low tire pressure/TPMS indicator and the appropriate tire indicator. If it detects a problem in the system, it turns on the low tire pressure/TPMS indicator (starts blinking).
The system consists of the following components:
- Keyless access/TPMS control unit
- Tire pressure sensors
- Initiators
- System indicator
For locations of each component on vehicle, refer to Component Location Index , and for functions of indicator, refer to How to Troubleshoot the TPMS .
Fill Assist
Overview
The fill assist function alerts the condition of the tire pressure when adjusting the tire pressure. The keyless access/TPMS control unit monitors the variation of tire pressure with the tire pressure sensor signal and outputs it to the MICU. The MICU will start to alert the condition of the tire pressure by flashing the turn signal/hazard lights and emitting beeps from the keyless buzzer.
System Diagram
Operating Condition
Fill assist function operates when all the following conditions are met:
- Ignition switch: ON mode
- Vehicle speed: 0 mph (0 km/h)
- Shift position: P position/mode
- Increase/decrease rate of pressure ≥15 kPa (0.15 kgf/cm 2, 2.2 psi)
However, the fill assist function may not operate under the following conditions:
- When increase/decrease rate of pressure does not reach 15 kPa within 1 minute.
- When using a portable handheld compressor.
Operation
The fill assist function operates the turn signal/hazard lights and keyless buzzer in three modes depending on the condition of the tire pressure. The system will also be activated when the tire pressure decreases (due to punctures, etc) and when all the criteria of the operating condition have been met. The system can only detect one tire that has the variation of tire pressure at a time. When inflating multiple tires consecutively, the system begins to monitor the first tire that reaches the operating condition. However, the tire pressures should be adjusted individually since the system is unable to detect which tire is on the operating condition first.