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TPMS: 2018-2020 Toyota CH-R

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This vehicle diagram shows the locations of (A) with a full size spare tire; (1) Tire Pressure Warning ECU and Receiver; (2) Tire Pressure Warning Valve and Transmitter; (3) Combination Meter Assembly - Tire Pressure Warning Light; (4) Main Body ECU (Multiplex Network Body ECU); (5) Steering Pad Switch Assembly and the (a) front of the vehicle.

| Photo credit: Mitchell 1

DESCRIPTION & OPERATION

When a tire pressure sensor is replaced or tires are rotated, the sensor ID must be memorized by the TPMS control unit.

DESCRIPTION OF SYSTEM

The tire pressure warning system warns the driver when the tire pressure has decreased in order to decrease CO2 emissions and enhance safety.

The tire pressure warning system illuminates the tire pressure warning light to warn the driver when the following condition is met:

Due to the operation of the steering pad switch assembly, the tire pressure drops to approximately 75% or less of the tire pressure set during system initialization. The tire pressure warning pressure (the pressure at which the warning light is illuminated) cannot be set to approximately 75% or less of a specified tire pressure value.

When the tire pressure warning system detects that the tire pressure of a tire is lower than the threshold, it will inform the driver using a warning light.

The tire pressure warning ECU and receiver receives the transmitter ID, temperature and tire pressure information from the tire pressure warning valve and transmitters. This information is used to determine when the pressure in one of the tires has dropped.

DESCRIPTION OF REGISTRATION

When tires and wheels are replaced, always ensure that each transmitter ID is correctly registered.

When one or more of the tire pressure warning valve and transmitters or the tire pressure warning ECU and receiver is replaced, the transmitter IDs for all of the tire pressure warning valve and transmitters must be re-registered. Before registering the transmitter ID of the new tire pressure warning valve and transmitter, check the Data List and record all of the transmitter IDs that are already registered.

TIRE PRESSURE WARNING RESET SWITCH

By operating the steering pad switch assembly, the tire pressure warning ECU and receiver can be set to issue a warning at an inflation pressure that corresponds to the type of tires fitted to the vehicle. Therefore, the warning threshold must be set to the proper value in order to comply with local regulations.

After the inflation pressures of all tires (except the compact spare tire) have been adjusted to the appropriate tire pressures, operate the steering pad switch assembly and perform initialization.

DESCRIPTION OF INITIALIZATION

During initialization, the tire pressure warning valve and transmitters measure the inflation pressure of the tires, and register the signals that are transmitted into the tire pressure warning ECU and receiver at a frequency of about once per minute. The initialization process is completed when signals from all tires (except the compact spare tire) have been received.

Perform initialization in these cases:

  • Before delivery of a new vehicle;
  • After replacement of the tire pressure warning ECU and receiver;
  • After replacement of a tire pressure warning valve and transmitter;
  • When the specified tire pressure changes due to the use of a different size or type of tire;
  • When the specified tire pressure changes due to a change in the vehicle load, the speed range that the vehicle will be used in, etc.;
  • When a tire rotation is performed and the specified tire pressures are different for the front and rear of the vehicle. Perform initialization after the transmitter ID registration is completed.

FUNCTION OF MAIN COMPONENTS

Tire Pressure Warning Valve and Transmitter: These components detect the pressure and internal temperature of the tire and transmit the measured values and the ID code to the tire pressure warning ECU and receiver.

Tire Pressure Warning ECU and Receiver: These components receive data from each tire pressure warning valve and transmitter and monitor tire pressures. When the tire pressure warning ECU and receiver detect a drop in the tire pressure, a system malfunction or initialization mode, they output the respective signal to the combination meter assembly. When the tire pressure warning ECU and receiver detect a problem with the vehicle speed signal, they use changes in the signal strength from the tire pressure warning valve and transmitter as a judgment standard. If the ECU detects any changes in the signal strength from the tire pressure warning valve and transmitter, it determines that the vehicle is being driven.

Steering Pad Switch Assembly: This is the switch that operates the multi-information display. “ENTER” switch. By operating this switch, a tire pressure warning threshold based on the current tire pressure is memorized as the set tire pressure in the tire pressure warning ECU and receiver.

Combination Meter Assembly: This transmits the vehicle speed signal to the tire pressure warning ECU and receiver.

Tire Pressure Warning Light: This illuminates after blinking for one minute to warn the driver in accordance with the signal from the tire pressure warning ECU and receiver. Displays two-digit Diagnostic Trouble Codes (DTCs).

Main Body ECU (Multiplex Network Body ECU): The main body ECU (multiplex network body ECU) and tire pressure warning ECU and receiver are connected using two direct lines that they use to communicate with each other. The main body ECU (multiplex network body ECU) is connected to the combination meter assembly via CAN bus.

TROUBLESHOOTING

TIRE PRESSURE WARNING ECU AND RECEIVER EXPRESSIONS

The type of tire pressure warning ECU and receiver used on this model differs according to the specifications of the vehicle. For vehicles with Smart Key System, the part name used here is tire pressure warning ECU and receiver. (The actual part name is the electrical key and tire pressure monitoring system receiver assembly.) For vehicles without a Smart Key System, the actual part name is the door control and tire pressure monitoring system receiver assembly.

TIRE PRESSURE WARNING SYSTEM PRECAUTION

Tire pressure decreases naturally over time, which also occurs in vehicle models without a tire pressure warning system. Tire pressure decreases by approximately 5 kPa (0.05 kgf/cm2 , 0.7 psi) to 10 kPa (0.1 kgf/cm2 , 1.5 psi) per month.

Tire pressures may need to be adjusted periodically.

In winter, tire pressure may decrease due to low ambient temperatures (tire pressure decreases by approximately 10 kPa (0.1 kgf/cm2 , 1.5 psi) for every 10°C (18°F) drop in the ambient temperature). Therefore, the tire pressure warning system is more likely to indicate a warning if the tire pressures are not adjusted appropriately. If the daily temperature variation is large, increase the pressure of the tires so that the tire pressures are suitable under cold conditions. As a result, unnecessary tire pressure warning operations should decrease.

Always use a new grommet and valve core when installing a tire pressure warning valve and transmitter to ensure the sealing performance.

When one or more of the tire pressure warning valve and transmitters or the tire pressure warning ECU and receiver is replaced, the transmitter IDs for all of the tire pressure warning valve and transmitters must be re-registered. Before registering the transmitter ID of the new tire pressure warning valve and transmitter, check the Data List and record all of the transmitter IDs that are already registered.

Use only a specified cap. If an unspecified cap is used, it may seize to the tire pressure warning valve and transmitter.

Depending on the tire type, the system may not function properly even if the specified wheels are used.

To prevent damage to the tire pressure warning valve and transmitter, make sure that the tire pressure warning valve and transmitter does not interfere with the tire bead when installing or removing a tire.

To prevent damage to the tire pressure warning valve and transmitter before disengaging the tire bead or removing the tire from the wheel, drop the tire pressure warning valve and transmitter into the wheel.

NECESSARY PROCEDURES WHEN REPLACING PARTS

ID Registration: When replacing the tire pressure warning valve and transmitter and tire pressure warning ECU and receiver, perform ID registration for the tire pressure warning valve and transmitter.

Initialization: After performing ID registration for the tire pressure warning valve and transmitter, make sure to initialize the tire pressure warning system.

TPMS RESET PROCEDURES

REGISTRATION

1. BEFORE REGISTRATION

The transmitter ID is written on the tire pressure warning valve and transmitter. It is not possible to read the transmitter ID after installing the tire onto the wheel. Therefore, make a note of the transmitter ID before installing the tire.

In case of tire pressure warning ECU and receiver replacement, read the registered transmitter IDs that are stored in the old ECU using the Techstream and write them down. If the reading the stored transmitter IDs is impossible due to malfunctions of components such as the tire pressure warning ECU and receiver, remove the tires from the wheels and check the IDs located on the tire pressure warning valve and transmitters.

In case of tire pressure warning valve and transmitter replacement, take a note of the seven-digit number (transmitter ID) written on the tire pressure warning valve and transmitter.

2. REGISTER TRANSMITTER ID (USING Techstream) HINT: The previously registered IDs will be cleared from memory when the registration is completed. If the ID registration step is not completed within 300 seconds, ID registration will be canceled. Follow these steps:

Set the tire pressure to the specified value;

Turn the ignition switch off;

Connect the Techstream to the DLC3;

Turn the ignition switch to ON and the Techstream on;

Enter the following menus: Chassis / Tire Pressure Monitor / Utility / ID Registration. Chassis > Tire Pressure Monitor > Utility; Tester Display: ID Registration

Perform the procedure displayed on the Techstream. It may take a few minutes until the values are displayed.

If the transmitter IDs have not been registered, DTC C2171/71 is stored in the tire pressure warning ECU and receiver after three minutes or more.

If normal pressure values are displayed, the transmitter IDs have been registered correctly.

If the tire pressure values are not displayed after a few minutes, the transmitter IDs may be incorrect or the system may have a malfunction.

After all transmitter IDs are registered, DTC C2126/26 is stored in the tire pressure warning ECU and receiver and the tire pressure warning light blinks for one minute and then illuminates. When the tire pressure warning ECU and receiver successfully receives signals from all the transmitters whose IDs are stored in the ECU, DTC C2126/26 is cleared and the tire pressure warning light goes off.

3.  CONFIRMATION OF TRANSMITTER ID REGISTRATION

Enter the following menus: Chassis / Tire Pressure Monitor / Data List. Chassis > Tire Pressure Monitor > Data List

Tester Display: ID 1 Tire Inflation Pressure, ID 2 Tire Inflation Pressure, ID 3 Tire Inflation Pressure, ID 4 Tire Inflation Pressure, ID 5 Tire Inflation Pressure.

Reduce the tire inflation pressure of each tire 40 kPa (0.4 kgf/cm2 , 5.8 psi) or more and check that the “ID Tire Inflation Pressure” data is updated and that the actual tire inflation pressures are displayed.

After confirming that all of the tire inflation pressure values (except the compact spare tire) have been updated, adjust the tire inflation pressure to the specified value, operate the steering pad switch assembly and perform initialization.

INITIALIZATION

Note that initialization can be confirmed through the tire pressure warning light.

If the ignition switch off during initialization, the tire pressure warning ECU and receiver memorizes that initialization was being performed. Therefore, it is not necessary to perform the initialization procedure again after turning the ignition switch to ON.

The order in which the data is received is random.

If the signals from all the tire pressure warning valve and transmitters are received, initialization is completed.

Initialization is completed when the Data List “ID Tire Inflation Pressure” display shows the correct pressures.

Initialization is normally completed within a few minutes. However, it may take 10 minutes or more until the tire pressure of the tire inflation pressure display function is shown.

It may take a few minutes until the values are displayed.

If initialization has not been completed successfully, DTC C2177/77 is stored after a vehicle speed of 40 km/h (25 mph) or more is detected for 20 minutes or more.

During test mode (sensor check mode), the system will not change to initialization mode even if the tire pressure warning reset switch is pushed.

Initialization can be terminated by connecting terminals 13 (TC) and 4 (CG) of the DLC3.

1.  BEFORE INITIALIZATION: Set the tire pressure to the specified value. The procedure for adjusting the tire pressures differs depending on the temperature of the tires.

2. INITIALIZATION PROCEDURE: The tire pressure warning system illuminates the tire pressure warning light to warn the driver when the following condition is met. Note that due to the operation of the steering pad switch assembly, the tire pressure drops to approximately 75% or less of the tire pressure set during system initialization:

Turn the ignition switch to ON;

Operate the steering pad switch assembly, select “TPMS” on the multi-information display and press and hold the “ENTER” switch (steering pad switch assembly) until the tire pressure warning light blinks three times:

*1 Tire Pressure Warning Light

*2 “ENTER” Switch (Steering Pad Switch Assembly)

*a Tire Pressure Warning Light Output Pattern

*b 1 sec.

*c ON

*d OFF

Turn the ignition switch off;

Connect the Techstream to the DLC3;

Turn the ignition switch to ON and turn the Techstream on.

Enter the following menus: Chassis / Tire Pressure Monitor / Data List. Chassis > Tire Pressure Monitor > Data List It may take a few minutes until the values are displayed;

Check that initialization has been completed;

Confirm that the tire pressure data of all tires is displayed on the Techstream screen.

REPLACEMENT PROCEDURES

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 demounting/mounting procedures.

TIRE PRESSURE WARNING VALVE REMOVAL

The necessary procedures (adjustment, calibration, initialization or registration) that must be performed after parts are removed and installed, or replaced during tire pressure warning valve and transmitter removal/installation are shown below:

• Replacement part or procedure

Replacement of tire pressure

Warning valve and transmitter

• Necessary procedures

Register transmitter ID

Initialize tire pressure warning system

• Effects/inoperative when not performed

When DTC detection conditions of “transmitter ID not received” DTC are met, TPWS indicator blinks for one minute, and then illuminates.

• Tire pressure warning function

When replacing the tire pressure warning ECU and receiver, read the transmitter IDs stored in the old ECU using the Techstream and write them down before removal.

PROCEDURE

Remove wheel assembly’

Remove tire pressure warning valve and transmitter. Keep the removed tire valve cap;

Remove the tire valve cap. Make sure that a sufficient amount of air has been released;

Remove the valve core to release the air from the tire;

Using an 11 mm deep socket wrench, remove the nut and washer;

Drop the tire pressure warning valve and transmitter with grommet into the tire. The grommet may remain attached to the wheel. Be careful not to damage the tire pressure warning valve and transmitter due to interference between the valve and the tire bead. Set the tire remover shoe as shown in the illustration;

Using a tire remover, remove the tire from the disc wheel;

Take out the tire pressure warning valve and transmitter with grommet from the tire;

Remove the grommet from the tire pressure warning valve and transmitter.

INSTALLATION

Always use a new grommet and valve core when installing the tire pressure warning valve and transmitter.

Check that the washer and nut are not damaged, and replace them if necessary;

Make sure not to damage the urethane covered backside of the tire pressure warning valve and transmitter (the surface opposite to the side with the ID code) with anything sharp;

Write down the ID number before installation;

Check that there is no oil, water or lubricant around the rim hole, tire pressure warning valve and transmitter, washer and nut. Failing to do so may result in improper installation;

Use only a specified tire valve cap. If an unspecified tire valve cap is used, it may seize to the tire pressure warning valve and transmitter.

PROCEDURE

Install tire pressure warning valve and transmitter. A new tire pressure warning valve and transmitter comes with a grommet installed. Make sure not to install an extra grommet.

Install a new grommet to the tire pressure warning valve and transmitter:

Write down the seven-digit transmitter ID number. Make sure that the tire pressure warning valve and transmitter is installed so that the printed surface can be seen. If the tire pressure warning valve and transmitter is installed upside down, it may be damaged or fail to transmit signals when driving at high speeds:

Check that there is no deformation or damage to the tire pressure warning valve and transmitter.

Check that there is no foreign matter on the grommet.

Insert the tire pressure warning valve and transmitter with grommet from the inside of the wheel. No further tightening is required once the nut is tightened to the specified torque. Check that there is no foreign matter on the grommet, washer and nut;

Install the washer to the tire pressure warning valve and transmitter from the outside of the wheel, and using an 11 mm deep socket wrench, tighten the nut. Torque: 4.0 N*m (41 kgf*cm, 35 in.*lbf);

Set the tire and disc wheel onto the mounting machine. Do not apply soapy water or equivalent directly to the tire pressure warning valve and transmitter;

Apply a sufficient coat of soapy water or equivalent to the tire bead and rim. Make sure that the tire bead and mount tool do not interfere with the tire pressure warning valve and transmitter. Make sure that the tire pressure warning valve and transmitter are not clamped by the bead and rim;

Using a mounting machine, install the tire to the disc wheel;

Install a new valve core;

Inflate the tire to the specified tire inflation pressure. (Note: No further tightening is required once the nut is tightened to the specified torque);

After the tire is inflated, the nut may be loose. Using an 11 mm deep socket wrench, retighten the nut to the specified torque: 4.0 N*m (41 kgf*cm, 35 in.*lbf) Check the surroundings of the tire pressure warning valve and transmitter for air leaks with soapy water or equivalent;

If air is leaking from the valve core, press the valve core several times to remove foreign matter. Replace the valve core as necessary. If air is leaking from around the tire pressure warning valve and transmitter, check if the grommet, washer and nut are not deformed, damaged or contaminated with foreign matter. Replace the grommet, washer or nut as necessary. Then follow these steps:

Install the tire valve cap;

Install wheel assembly;

Inspect tires;

Register transmitter ID;

Inspect tire pressure warning system;

Perform initialization.

 


Information for this column comes from the tire pressure monitoring systems data in ProDemandR, 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

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