The TPMS transmitters are located on the wheel well and have a built-in tire pressure sensor (see Figure 1). The transmitter measures the tire pressure and sends the data as a radio frequency (RF) signal to the TPMS antenna. The antenna translates the RF signal and sends the translated signal to the TPMS receiver.
The TPMS receives the signal and determines whether the TPMS warning indicator needs to be illuminated. When the ignition switch is in the ON position, the tire pressure warning light will remain illuminated if one or more of the tires have low pressure.
To remove an old sensor, follow these steps.
1. Raise the vehicle on a suitable support. Remove the tire/wheel assembly from the vehicle.
2. Remove the valve cap.
3. Rotate the tire so that the valve stem is in the 6 o’clock position.
4. Using a long-reach (0.68-inch) socket, unscrew the valve nut a few turns. See Figure 2. Slowly push the valve stem into the tire so that the tire pressure is relieved.
5. Once the tire pressure is relieved, remove the valve nut. NOTE: Damage to the TPMS transmitter may occur at this stage; use caution.
6. Place on a tire changing machine. Break both tire beads, ensuring that the tire pressure sensor remains in the bottom of the tire.
7. Lubricate the tire well, and remove the outer side of the tire.
8. Reach inside the tire and remove the TPMS transmitter.
9. Using a soft tool to prevent scratching the valve, remove the grommet from the TPMS transmitter.
To install a new sensor, follow these steps.
1. Slide the inner tire bead over the rim face. Use lubricant, as normal procedures require. NOTE: Visually check that the TPMS transmitter is not deformed or damaged. Ensure the rim, grommet and valve nut are clean.
2. Install a new grommet to the TPMS transmitter. NOTE: While installing the valve nut, ensure the tool is kept aligned to the valve and valve hole.
3. Ensure the grommet is located inside the valve hole before installing the valve nut. While installing the valve nut, hold the valve and grommet firmly in contact with the rim. After installing the valve nut, ensure the grommet is compressed.
4. Mount the TPMS transmitter valve through the rim hole as shown in Figure 2. Both holes in the sensor case should face away from the center of the rim. Tighten the valve nut finger-tight, and then slowly tighten the valve nut to 45-53 in.-lbs. (5-6 N.m).
5. Ensure the TPMS transmitter is correctly assembled. One side of the lower lip of the TPMS transmitter case can touch the rim after torqueing. Except for the grommet, the valve nut and the lower lip of the TPMS transmitter, no other part of the front of the TPMS transmitter case should be touching the rim.
6. Place the wheel and the tire on the turntable of the tire mounting machine. Ensure that the transmitter is 270 degrees (3 o’clock position) from the mounting head when the outer tire bead is mounted as shown in Figure 3. Lubricate the tire well, and mount the outer tire bead as normal. Ensure that the tire does not rotate during mounting.
7. Install the tire on the wheel. Install the tire/wheel assembly on the vehicle.
8. Inflate the tire to specification. After tire inflation, retighten the valve nut to 49 in.-lbs. (5.5 N.m). This is necessary, as the TPMS transmitter is secured to the wheel with the valve nut and rubber grommet. The rubber grommet will be depressed by the tire pressure or deteriorate over a period of time, which requires the valve nut to be retightened.
9. Register the TPMS transmitter. NOTE: If the TPMS receiver or transmitter is replaced, the tire pressure sensors must be registered.
To register a sensor, follow these steps. The following tools are required when performing the tire pressure registration: scan tool MUT-III sub Assembly (MB991958); vehicle communication interface (VCI) (MB991824); a MUT-III USB cable (MB991827); and a MUT-III main harness A (MB991910).
CAUTION: To prevent damage to the scan tool (MB991958), always turn the ignition switch to the OFF position before connecting or disconnecting the scan tool.
1. Connect the MUT-III (MB991958) scan tool to the Data Link Connector (DLC), with the ignition switch in the OFF position.
2. Turn the ignition switch to the ON position. NOTE: Register all tire pressure sensors IDs within 20 minutes.
3. Select “4 SNSR ID REGISTRATION (CHANGE TIRE PRS)” and start tire pressure sensor ID registration. NOTE: If the ID registration is not completed within 20 minutes, all the TPMS transmitter IDs previously registered will be erased. The ID registration must be repeated.
4. Verify the scan tool displayed “4 SNSR ID REGISTRATION Do you want start?” Press OK. NOTE: The following operations may be started from any TPMS transmitter. The sensor ID registration has no order.
5. Register the TPMS transmitters IDs by decreasing the tire pressure to 25.2 psi or less in 2.9 psi increments.
6. Write down each TPMS transmitter ID that displays on the scan tool screen. The MUT-III scan tool cannot identify which registered TPMS transmitter ID is used for each tire. NOTE: The TPMS warning indicator will illuminate, because tire pressures are low.
7. When “4 SNSR ID REGISTRATION COMPLETED” is displayed, press OK.
8. Turn the ignition switch to the OFF position and remove the scan tool.
9. Wait one or more minutes, and then adjust the tire pressure to the specified values. NOTE: If the TPMS warning indicator is illuminated, drive the vehicle for five minutes and check the TPMS warning indicator. If the TPMS warning indicator is still illuminated, registration must be repeated.
10. Ensure the warning indicator does not illuminate or flash. ■
Information for this column comes from Mitchell 1’s ”Tire Pressure Monitoring Systems Guide” for domestic and import vehicles through 2010. Headquartered in Poway, Calif., Mitchell 1 has provided quality repair information solutions to the automotive industry for more than 80 years. For more information, visit www.mitchell1.com. See more archived TPMS articles on www.moderntiredealer.com