When a vehicle comes into the bay with a telltale TPMS light on, its TPMS system is signaling an issue that needs to be addressed. The tire dealership’s task is finding out what that issue is.
Luckily, there’s some guidelines for most systems that let you know what it’s communicating. For example, if a TPMS light blinks for 30-90 seconds before remaining solid, it indicates that the failure has something to do with the system itself, whereas a solid light indicates that one or more tires is below placard pressure. A blinking light tells you that the issue is more than likely one or more failing sensors. Some newer vehicles will display pressure by location on the dashboard that can show the location of the faulty sensor. However, there are some vehicles on the road that still need to be diagnosed to discover which wheels hold faulty sensors.
In order to diagnose the system, you first need to connect to the OBDII port on the vehicle and download any Diagnostic Trouble Codes (DTCs) stored in the vehicle’s ECU. If the process is done correctly, the DTC should highlight which sensor(s) is failing and needs to be replaced. It may even indicate if a sensor battery is low. In this case, it is always best to recommend that the driver replace all four sensors during a single service, especially if they are still original sensors. When one sensor dies, the rest will likely follow shortly after. Replacing all sensors will save time and money for the driver in the long run.
Your second option would be to open up the “diagnose” section of your TPMS tool menu and start the diagnostic sequence. The process will vary depending on the tool manufacturer, but at some point in the process, it will have you walk around the vehicle to test each sensor in a specific order: LF, RF, RR, LR and spare (if required).
To test the sensor, hold the tool scanner against the tire wall directly above the valve and scan the sensor. One or more of the sensors will come up faulty during this test and should indicate the sensor that needs repaired.
Always remember that whether you use a programmable sensor solution or a “plug-and-play” type solution, you will need to relearn the new sensors to the vehicle after installing them. The relearn procedure is responsible for telling the vehicle which tire each sensor is located in. Therefore, if the relearn is not performed correctly, the vehicle will not display the correct pressure for the correct tire, causing the driver to come back.
Check out the rest of the February digital edition of Tire Review here.