SUBJECT VEHICLE: 2007-10 Acura MDX.
RELEARN PROCEDURE? Yes, directions follow.
SPECIAL TOOLS NEEDED? No.
Whenever the engine is running on the 2007-10 Acura MDX, the tire pressure monitoring system (TPMS) control unit continuously monitors all four tires. The system has seven indicators: four tire indicators; a low pressure indicator; a message indicator; and a TPMS system indicator.
If the TPMS control unit detects pressure below 25 psi, it alerts the driver by turning on the low pressure indicator and turning on the appropriate indicator on the multi-information display. The control unit also turns on the message indicator and sets a diagnostic trouble code (DTC) in the control unit. When the pressure is increased to normal, the control unit will turn off the indicators and store the DTCs.
To remove an old sensor, follow these steps. NOTE: Vehicles equipped with TPMS must use wheels made for the system, or the system will not work. The original equipment wheels have a TPMS mark on them, and a counterweight cast into the opposite side of the spoke to balance the weight of the sensor (see Figure 1).
1. Raise the vehicle, and support it with safety stands in the proper locations.
2. Remove the wheel with the faulty sensor.
3. Remove the tire valve cap and valve core, and let the tire deflate.
4. Remove any balance weights, and then remove the tire from the wheel. Note these items to avoid damaging the tire pressure sensor: Do the outside of the wheel first. Position the wheel as shown 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. Position the wheel so the tire machine and tire iron are next to the valve stem and will move away from it when the machine starts. Then remove the tire from the wheel.
5. Remove the valve stem nut and washer, and then remove the tire pressure sensor/valve stem assembly from the wheel. NOTE: The valve stem grommet might stay in the wheel; make sure to remove it.
6. Remove and discard the valve stem grommet from the tire pressure sensor.
To install a sensor, follow these steps. NOTE: Use a new nut, valve stem and screw.
1. Install the new valve stem grommet on the sensor-transmitter.
2. Before installing the tire pressure sensor, clean the mating surfaces on the sensor and the wheel.
3. Install the tire pressure sensor to the wheel, install the washer and tighten the valve nut finger tight. Make sure the sensor is resting on the wheel (see Figure 2).
4. Tighten the valve nut to 3 ft.-lbs. (4 N.m) while holding the tire pressure sensor toward the wheel and take the following precautions: Do not use air or electric impact tools to tighten a valve stem nut. Tightening the nut beyond the specified torque can damage the nut. Make sure that there is no space between the sensor and the wheel.
5. Lube the tire bead, and position the wheel so the tire machine and tire iron are next to the valve stem and will move away from it when the machine starts. Then install the tire onto the wheel. NOTE: Make sure the tire bead is seated on both sides of the rim uniformly.
6. Inflate the tire to 44 psi (300 kPa) to seat the tire bead to the rim, then adjust the tire pressure to specification, and install the valve stem cap.
7. Check and adjust the wheel balance, then install the wheels to the vehicle.
8. Remove the safety stands, and lower the vehicle.
9. Memorize the pressure sensor IDs.
To memorize the sensor ID automatically, follow these steps.
1. After rotating the tires or replacing a tire pressure sensor, drive the vehicle for at least 40 seconds at a speed of 15 mph or more, and all the sensor IDs will be memorized automatically
2. After the 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.
To memorize the sensor ID using the Hitachi Data System (HDS), follow these steps.
1. With the ignition switch in the OFF position, connect the HDS to the 16-pin Data Link Connector (DLC) located under the left side of the dashboard.
2. Turn the ignition switch to the ON position, and memorize the ID of the tire pressure sensor by following the screen prompts on the HDS. If all IDs are memorized properly, go to step 4. If the TPMS control unit fails to memorize one or more sensor IDs during the learning process, go to the next step.
3. If one or more IDs fail to learn, causing DTCs to set, the HDS will provide a procedure to fix this that involves raising the vehicle. To solve this problem much faster, do this:
a. Using HDS, clear all DTCs.
b. Using an assistant, start the learning process while driving the vehicle under 10 mph. The TPMS control unit should now learn all four sensor IDs. If it is still having trouble learning IDs, refer to the appropriate service information.
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.