Featured TPMS Tip: Acura RLX (Except Hybrid) 2016-2020
Mitchell 1 provides TPMS information to Modern Tire Dealer, an award-winning publication that writes editorial content geared to independent tire dealers. We’re sharing this content in our blog, with a link to the Modern Tire Dealer website where you can read the article in full. The TPMS information in this article may also be accessed in the reset procedures tab in our ProDemand® auto repair information software, along with other important reset procedure data for the selected vehicle.
NOTE: When a tire pressure sensor is replaced or tires are rotated, the sensor ID must be memorized by the tire pressure monitoring system (TPMS) control unit. See TPMS RESET PROCEDURES.
TPMS System Description — Components
TPMS Control Unit
The TPMS control unit sends signals to the initiators and receives signals from the tire pressure sensor to verify pressure sensor IDs every time the vehicle is turned to the ON mode. It also receives signals from the transmitters for tire pressure, tire temperature and the sensor battery condition and it continuously monitors and controls the system.
Tire Pressure Sensor
A tire pressure sensor is an integrated unit made up of each tire valve stem, a pressure sensor and a transmitter. Tire pressure sensors are attached to the inside of each wheel around the valve stem. The sensor transmits internal tire information using a radio frequency (RF) band wave signal one time per 60 seconds to the TPMS control unit. Each tire pressure sensor has its own tire pressure sensor ID to prevent jamming by similar systems on other vehicles.
The initiators are mounted on the top of each wheel well. When the vehicle is turned to the ON mode, the initiators send a low frequency (LF) band wave signal to the tire pressure sensors, switching them from sleep mode to normal function mode. When the vehicle is turned to the OFF (LOCK) mode, the sensors switch from normal function mode back to sleep mode to extend their battery life.
The TPMS will not work unless TPMS-type wheels are installed on the vehicle. The original equipment wheels have a “TPMS” mark on them and are counterweighted by adding material to counterbalance the weight of the tire pressure sensor.
TPMS System Description — Overview
The TPMS 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 and starts blinking. The system consists of the following components: (See Figure 1):
• Keyless access/TPMS control unit;
• Tire pressure sensors, and
TIRE PRESSURE MONITOR WARNING INDICATORS
The multi-information display (MID) provides the odometer/trip meter, outside air temperature, average fuel efficiency, available cruising range, instant fuel economy, elapsed time, TPMS, gear position, oil life, seat belt reminder, average speed and the status of the keyless access system. In addition, the diagnostic system displays the communication errors and diagnostic trouble codes (DTCs).
Here’s how to troubleshoot the TPMS system indicator. The system has seven indicators. (See Figure 2):
• The low tire pressure indicator (A);
• The message indicator (B);
• The TPMS indicator (C);
• The right-front (RF) tire indicator (D);
• The left-front (LF) tire indicator (E);
• The right-rear (RR) tire indicator (F);
• The left-rear (LR) tire indicator (G).
The Low Tire Pressure Indicator
If the system detects low tire pressure in any of the four tires, the low tire pressure indicator and the appropriate tire indicator(s) come on, as well as the message indicator.
If the TPMS control unit detects a problem in the system during an indication of low tire pressure, it will turn off the tire indicator(s), store the DTC(s) and turn on the TPMS indicator and the low tire pressure indicator after blinking.
The TPMS Indicator
• If a problem in the system is detected, the TPMS indicator comes on, as well as the message indicator, and the low tire pressure indicator comes on after blinking for about 75 seconds.
• If low tire pressure and a problem in the system are detected, the TPMS indicator comes on, as well as the message indicator, and the low tire pressure indicator comes on after blinking for about 75 seconds.
• If the system is OK, the low tire pressure indicator should come on when you turn the vehicle to the ON mode, and then goes off two seconds later. If it does not, there is a problem with the system.