Most vehicles require some type of “stationary” relearn procedure to reset the system. This requires some type of TPMS tool to activate each of the tire pressure sensors in a specified sequence so the TPMS control module can relearn their new locations. On some GM applications, a J-41760 magnetic tool is required to “wake up” the sensors. On most other applications, a factory TPMS tool or an aftermarket TPMS tool that broadcasts a radio signal is needed for the sensor position relearn procedure.
On some applications, the TPMS relearn tool can be connected to the vehicle’s OBDII diagnostic connector to read and clear codes, display system data and perform sensor ID programming. On many Asian and European applications, each individual tire pressure sensor has a unique ID code. Vehicles that currently require this kind of reprogramming include most Hyundai, Infiniti, Kia, Lexus, Mitsubishi, Nissan, Subaru, Suzuki and Toyota models. If one or more sensors has been replaced, the new ID information has to be inputted directly into the system. So, if you don’t have a TPMS tool that can do this, your only alternative is to send your customer back to the new-car dealer to have the ID reprogramming done.
TPMS relearn procedures vary a great deal from one vehicle to the next, so you also need access to the TPMS service data for the vehicle, or a reference manual or chart that covers the relearn procedures. Without this vital information, you can’t reset the system.
Essentially, most relearn procedures require you to put the system into a relearn mode. On some, this may require a command from a scan tool or plug-in TPMS tool. Or, you may have to cycle the ignition key on and off a certain number of times while stepping on the brake pedal. On others, the keyless entry fob may be used to wake up the TPMS module and ready it for relearning.
When the TPMS is ready, it may signal by beeping the horn or flashing the hazard lights. The TPMS activation tool is then placed near one of the tire pressure sensors, and a button is pressed for five or six seconds to wake up the sensor. As soon as the TPMS module recognizes the sensor and learns its position, the system signals again by beeping the horn or flashing the hazard lights. You then repeat the same procedure for each of the remaining tire pressure sensors in the specified order until the relearn procedure is complete.
Scan tools or dedicated TPMS tools that can interface through the OBDII connection can have advantages when it becomes too difficult to reprogram vehicles — even on vehicles that have key fob or DIC relearn procedures.
With some procedures requiring a J-41760 magnetic tool, you may be flying blind. Problems with the key fob, antenna and even the module or serial data bus connection can leave you chasing your tail. With a scan tool or dedicated TPMS tool, it is possible to perform a more accurate relearn and diagnosis.