TPMS Instructions: Acura RLX (Except Hybrid) 2016-2020
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.
Tire Pressure Changing by Temperature
Tire pressures increase slightly as the temperature in the tires rise during driving. Pressures can also increase or decrease slightly with changes in outside air temperature. A temperature change of about 18 degrees F (10 degrees C) changes tire pressure by about 1.5 pounds per square inch (psi).
If the temperature drops, tire pressure could decrease enough to turn on the low tire pressure indicator and tire indicator(s), but later, the tire temperature could increase enough to turn the indicator off. To resolve a complaint of such intermittent indications, confirm and clear the stored.
Then explain to the client how temperature changes can affect the system.
Problems That Are Not System Faults
• Tire sealant: Fluid sealant used to repair a punctured tire can damage the tire pressure sensor mounted on each wheel. It can prevent the system from detecting the correct tire pressure, which sets a DTC 11, 13, 15 or 17, even though the system is normal.
• Cold weather: When the weather is extremely cold, about minus-4 degrees F (minus-20 degrees C) or colder, the output of the lithium battery in each tire pressure sensor may drop far enough that the TPMS control unit sets a DTC for low battery voltage (31, 33, 35 or 37), even though the system is normal.
• Non-TPMS-type wheels, including spare tire: Vehicles equipped with TPMS must use wheels made for the system. Every TPMS type wheel has an exclusive mark. Do not use any other type of wheel. When a flat tire is replaced with the spare tire, the TPMS indicator comes on (DTC 32, 34, 36 or 38) because the system is no longer receiving the signal from the flat tire’s transmitter. This is not a problem with the spare tire.
TPMS RESET PROCEDURES
Tire Pressure Sensor Registration
Memorizing the Tire Pressure Sensor ID:
• Note that: To ensure the TPMS control unit memorizes the correct sensor ID, the vehicle with the new tire pressure sensor must be at least 10 feet (3 meters) away from other vehicles that have sensors;
• When replacing the keyless access/TPMS control unit, use the Honda & Acura Diagnostic System (HDS) to memorize sensor IDs.
NOTE: After the sensor IDs are memorized, reduce the pressure in all four tires to less than the appropriate specification and check to see that the four-tire indicators come on.
• When replacing the keyless access/TPMS control unit, use the HDS to memorize sensor IDs;
• After the sensor IDs are memorized, reduce the pressure in all four tires to less than the appropriate specification and check to see that the four-tire indicators come on.
Tire pressure sensor ID
All four sensor IDs must be memorized to the TPMS control unit whenever you do any of these actions:
• Replace the keyless access/TPMS control unit;
• Replace the tire pressure sensor, and;
• Substitute a known-good wheel with a tire pressure sensor.
Memorizing a tire pressure sensor ID automatically
After rotating the tires or replacing a tire pressure sensor, drive the vehicle for at least 40 seconds at a speed of 15 mph (24 km/h) or more and all the sensor IDs are memorized automatically.
Memorize a tire pressure sensor ID with the HDS
The HDS can memorize the sensor ID of a new tire pressure sensor or a previously memorized sensor ID.
1. Turn the vehicle to the OFF (LOCK) mode;
2. Connect the HDS to the data link connector (DLC) located under the driver’s side of the dashboard;
3. Turn the vehicle to the ON mode;
4. Make sure the HDS communicates with the vehicle and the TPMS control unit;
5. Memorize the tire pressure sensor ID by following the screen prompts on the HDS, and;
6. Turn the vehicle to the OFF (LOCK) mode.
CAUTION: The tire should be demounted from the wheel using the tire changer manufacturer’s instructions. Use the following information to avoid damage during the process.
Tire Pressure Sensor Removal and Installation
NOTE: Each tire pressure sensor contains a lithium anode battery that is not removable. The complete tire pressure sensor should be disposed of according to local battery disposal guidelines. Improper battery disposal can be harmful to the environment.
1. Vehicle — lift
2. Remove wheel with the faulty tire pressure sensor
3. Tire pressure sensor — remove
• Remove the tire valve stem cap and the valve stem core to deflate the tire;
• Remove any balance weights.
NOTE: Note these items to avoid damaging the tire pressure sensor:
• Do the outside of the wheel first;
• Position the wheel so the valve stem is 90 degrees from the bead breaker;
• Do not position the bead breaker of the tire changer too close to the rim;
• Break the bead loose from the wheel with a commercially available tire changer (A). (See Figure 3)
• Position the wheel so that the tire machine (A) and the tire iron (B) are next to the valve stem(C) and will move away from it when the machine starts;
• Remove the tire from the wheel.
NOTE: Check the nut and the washer. If they are deteriorated or damaged, replace them with new ones during reassembly.
Remove the valve stem nut (A) and the washer (B); remove the tire pressure sensor with the valve stem (C); and remove and discard the valve stem grommet (A). The valve stem grommet might stay in the wheel. Make sure you remove it. And always use a new valve stem grommet whenever the tire pressure sensor has been removed from the wheel or when replacing the tire.
Tire Pressure Sensor — Install
NOTE: Use only wheels that have a “TPMS” stamp (A) on the inside or outside of the wheels. (See Figure 4):
1. Before installing the tire pressure sensor, clean the mating surfaces;
2. Install the tire pressure sensor (A) NOTE: Install the sensor so that the sensor housing surface (D) is below the protrusion (E) of the wheel. This prevents the sensor housing from being caught on the bead during installation. Be sure to always mount the tire pressure sensor with the feet (F) in the downward position toward the wheel;
3. Install the washer (B) and the valve stem nut (C);
4. Tighten the valve stem nut to the specified torque while holding the tire pressure sensor:
Do not use air or electric impact tools to tighten the valve stem nut.
Do not twist the tire pressure sensor to adjust its position with the wheel, as this will damage or deform the valve stem grommet.
5. Lube the tire bead sparingly with a paste-type tire mounting lubricant and position the wheel so that the tire machine (A) is next to the valve stem (B) and will move away from it when the machine starts;
6. Install the tire onto the wheel and make sure the tire bead is seated on both sides of the rim evenly;
7. With a dry air source, inflate the tire to 43.5 psi to seat the tire bead to the rim;
8. Adjust the tire pressure;
9. Install the valve stem cap, and;
10. Check and adjust the wheel balance.
Information for this column comes from the tire pressure monitoring systems data in ProDemand, Mitchell 1’s auto repair information software for domestic and import vehicles. Headquartered in San Diego, Mitchell 1 has provided quality repair information solutions to the automotive industry since 1918. For more information, visit www.mitchell1.com.