The tire pressure monitoring system (TPMS) primary function is to make the driver aware of the state of tire pressure within the wheels.
When the tire sensor indicates “low tire pressure”, the TPMS system sends an RF signal to the ECU on the vehicle that determines if the pressure is below the threshold, which then will indicate a TPMS symbol or position-specific display, depending on the vehicle.
There are two types of TPMS systems:
- Direct TPMS
The direct TPMS systems use TPMS sensors inside the wheel to report pressure data to the vehicle’s ECU in real time, covering Asian, Amercian and European vehicles, which are more accurate and reliable to indicate which tire is underinflated. - Indirect TPMS
The indirect TPMS system uses an ABS system to monitor the speed of the wheel and communicate to the ECU, covering Asian and some European vehicles.
Indirect systems are less reliable since they cannot tell the driver which tire is low on pressure, and won’t warn the driver if all four tires are losing pressure at the same time.
When a service has been performed to the direct TPMS system, such as air pressure adjustment, tire rotation or replacement of sensors, most vehicles will require a TPMS system relearn to be performed.
Relearn procedures vary by manufacturer, so a technician must know if a relearn procedure is necessary to put the vehicle in “learn” mode.
Although relearn procedures differ from manufacturer to manufacturer, the 3 types of relearn procedures are:
- Auto Relearn
- Stationary Relearn
- OBD Relearn.
Furthermore, some vehicles may use a combination of two or more relearn types.
Indirect TPMS systems use an initialization procedure which may require a TPMS tool to figure out the steps involved to reset the system.
The chart below represents the three types of TPMS relearn procedures within the market of Asian, Amercian and European vehicles equipped with direct TPMS systems.
An auto relearn procedure is when a vehicle has the ability to learn a single or multiple TPMS sensor IDs without the need of performing the procedure with a TPMS tool.
Furthermore, a technician can adjust the inflation pressure, rotate or replace sensors and the TPMS system will reset itself after the vehicle has been driven for a period of time.
Before servicing the tires/wheels, it is always recommended to use a TPMS tool to trigger each of the vehicle’s sensors to make sure they are working properly.
For example, a 2008 Dodge Charger requires an auto relearn procedure:
- Inflate all tires
- Drive for 20 minutes
A stationary (sometimes called manual) relearn procedure allows new TPMS sensor IDs to be transferred to the vehicle’s ECU without driving a vehicle.
This type of relearn procedure requires a TPMS activation tool to trigger the sensors when the vehicle is in learn mode either by using a TPMS diagnostic tool or diagnostic scan tool. The vehicle then uses an RF signal to communicate with the vehicle’s ECU to establish which sensor is in which specific location.
For example, a 2014 Ford Escape (with standard ignition) requires a stationary relearn procedure:
- Inflate all tires
- Turn ignition off
- Press and release brake pedal
- Cycle ignition from “off” to “run” three times ending in “run”
- Press and release brake pedal
- Turn ignition off
- Cycle ignition from “off” to “run” three times ending in “run”
- Horn sounds twice
- Use tool to activate left front sensor
- Single horn will sound
- Repeat for right front sensor, right rear sensor, left rear sensor
An OBDII relearn procedure requires a TPMS scan tool to transfer new sensor IDs directly to the vehicle’s ECU.
The user would need to scan each TPMS sensor, connect to the vehicle’s OBD port, then follow the step-by-step instructions on the tool. The new TPMS sensor IDs are then transferred to the vehicle.
Most Asian and specialty European vehicles require OBD relearn. For example, a 2011 Toyota Camry requires an OBDII relearn procedure:
- Inflate all tires
- Read all sensor IDs using TPMS scan tool
- Connect tool to OBDII port
- Reset ECU with tool
- Turn ignition OFF, then ON
- Drive at 12 mph for up to 5 minutes
Autel TS508 TPMS Relearn and Programming Tool with 2 Modes Options
4.6 / 5an OBDII TPMS service tool mainly serviced for TPMS related tasks.
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The Autel Ts508 is an innovative TPMS diagnostic and service tool. Made with professionals in mind, this TPMS tool is perfect for any car enthusiast. The Autel Ts508 works by activating TPMS sensors to check, diagnose and even correct problems. With a user-friendly interface, this tool is recommended for at-home use by professionals and non-professionals alike.
Pros
- Two Modes: Quick Mode and Advanced Mode
- Large display screen
- Lifetime free software update
- One-year warranty service
- Comprehensive coverage of domestic, European and Asian car models.
Cons
- Expensive (but relatively affordable given the professional services the tool provides)
- Difficult to install software updates which are necessary for some newer model vehicles
Manual and stationary relearn systems can sometimes take several steps to relearn the TPMS system. TPMS tools, such as the Autel TS508, have the step-by-step instructions for auto, stationary and OBD relearn, however, the steps involved can be long and complicated.
OBD relearn procedures are becoming standard in a shop environment for many reasons.
First and foremost, it is the easier to work with since the same procedure can be performed no matter what the vehicle type is.
Secondly, OBD relearn saves time and confusion for the technician since there are less steps to perform.
At 86%, Autel TS508has the largest percentage of OBD relearn protocols in their TPMS tools than any other TPMS tool company.