TPMS Service Tips for Auto Service Professionals

• Always work with the most recent tool software. Out-of-date TPMS tool software is the most frequent cause of relearning issues.
• Use only TPMS-specific service kit parts. Never use a standard brass valve core in a TPMS sensor.
• Always use new TPMS service kit parts. Never reuse service parts that have been previously installed.
• Always use a torque tool to tighten sensor hex nuts or other threaded TPMS components to proper specifications.
• TPMS sensors only need to be replaced if they’ve been damaged, or if the battery is worn out.
• Always check the spare tire to determine if it’s TPMS-equipped and working properly.
• Replacement TPMS sensors must be relearned to the vehicle, plus a relearn may also be required after performing a tire rotation.
• When working on any service that uncovers a control unit or wiring, carefully seal the components to protect them from moisture or chemical exposure. If they are not protected, TPMS sensors can experience problems, including inaccurate pressure readings.

Even among experienced service pros, there are still many questions about TPMS service. One of the most common questions we hear is, “What is the difference between TPMS relearn and TPMS programming?” Here’s the answer:

TPMS sensor programming is an extra TPMS service step

TPMS vehicle relearn and TPMS sensor programming are completely different procedures. Aftermarket TPMS sensors that come as “programmable,” “universal,” or “cloneable” must be programmed with the proper protocol/application information for the specific vehicle before they can be installed. Once they have been successfully programmed, they must then be relearned to the vehicle.

Multi-application sensors are pre-programmed

Since REDI-Sensors are multi-application TPMS sensors, they need no cloning or programming. They come out of the box with the proper programming needed to function with multiple vehicles’ TPMS. However, like every TPMS sensor, OE or aftermarket, they must be relearned to the vehicle, and a TPMS tool with updated software may be required. Because they are pre-programmed, REDI-Sensor Multi-Application TPMS Sensors eliminate the time spent on programming, troubleshooting, and cloning issues. This helps make TPMS service more profitable and reduces customer complaints and comebacks. 

Vehicle relearn is always a required TPMS service step

Whether it is an OE sensor, a programmable sensor, or a multi-application sensor, every aftermarket TPMS sensor must be ‘relearned’ to the vehicle. The relearn procedure not only connects the sensor to the vehicle's TPM System but also verifies that the vehicle’s TPM System is functioning properly. With the exception of some Chrysler and Mazda models that may be relearned through a driving procedure, a TPMS scan tool is required to complete the relearn procedure.

One of the easiest ways to speed up TPMS work in your shop is to eliminate the need to call your supplier and wait for a TPMS sensor delivery. By keeping the four REDI-Sensors Multi-Application TPMS Sensors on hand, you’ll be ready to work on almost every vehicle in your shop. Instead of waiting for a parts delivery or spending time programming a ‘universal’ sensor, you can get right to work on your customer’s vehicle.

To be ready to service most of your customers with OE sensors, you would need to keep dozens of different sensors on hand. To be ready for your customers with REDI-Sensor, you just need a handful.

Why would I need dozens of OE sensors?

A lack of standardization and a wide variety of OE and aftermarket TPMS sensors on the market have led to tremendous proliferation of TPMS parts. Many of these sensors require distinct RF protocols and operate in unique modes. Parts stores have struggled to keep up with the huge number of TPMS sensors now on the market.

Some manufacturers have tried to address the proliferation of TPMS sensor parts by offering ‘universal’ sensors supplied as blanks that must be programmed before installation. These programmable sensors may require technicians to learn specialized relearn procedures that differ from OE procedures. Many of the TPMS service issues shops experience today stem from programming issues with these ‘universal’ sensors.

Avoid TPMS sensor programming delays

REDI-Sensor needs no programming, so there are never any programming hang-ups. It is a true multi-application TPMS sensor, and each REDI-Sensor can be used on a variety of makes and models. REDI-Sensor works with most major scan tools with up-to-date software, so you don’t have to purchase additional scan tools and software upgrades or undergo special training. If your scan tool is an Autodiagnos, Bartec, OTC, ATEQ, or T.I.P.S., you’re ready for REDI-Sensor.

TPMS sensor service kit parts must be replaced during every tire service, including flat-tire repairs and new-tire mounting. Even when a full sensor replacement is unnecessary, the service parts should be replaced.

The service kit for sensors with a metal stem generally consists of a hex nut, grommet/seal, valve core, and cap. For sensors with a rubber stem, the kit includes a completely new stem, core, and cap.

Before the introduction of TPMS, a tire valve was a simple part. Either it held air, or it didn’t; if it didn’t, you replaced it. Now, with TPMS, the valve assembly is an integral part of an essential safety system that’s been mandated by Federal law. If the valve assembly is compromised, the entire Tire Pressure Monitoring System is compromised. 

Service parts can corrode and lose proper functionality over time. Replacing the TPMS service parts is needed to ensure you return the vehicle to the customer with the tire safety system operating as designed. 

There are several types available for service on today’s vehicles:

OE replacement sensors - Identical to the original equipment and pre-programmed for the specific vehicle.

Programmable or ‘universal’ sensors - These aftermarket sensors come as blanks and require programming for the specific vehicle prior to installation. It’s an additional service step that requires a programming tool and specialized software.

Multi-application / Multi-protocol sensors - These aftermarket sensors are pre-programmed for a range of vehicles and come ready to use out of the box. As with OE sensors, no sensor programming is required for multi-application/multi-protocol TPMS sensors.

The TPMS vehicle relearn procedure is a specific set of steps established by the vehicle manufacturer to activate and confirm the communication between the vehicle TPMS system and the TPMS sensors mounted in the tires.

A vehicle relearn is always required during sensor replacement (as well as other sensor or tire work), whether you are using an OE, universal, or multi-application sensor. Some vehicles relearn automatically when you drive them, while others require a TPMS scan tool to complete the relearn.

A Tire Pressure Monitoring System (TPMS) sensor is engineered to survive and perform under harsh road conditions. Its typical operational lifespan is 5 to 10 years, depending on the sensor type, vehicle use, and other conditions.

TPMS sensor batteries are sealed in the sensor housing and cannot be serviced. When the battery is depleted, the sensor can no longer provide protection to the driver and passengers and must be replaced.
Key factors affecting sensor battery life include:

Driving vs. parked - More transmissions are sent while the vehicle is driving, which uses more battery energy.

Sensor specifications - Some sensors have an additional factory-enabled parking-supervision mode, whereas others transmit only during motion.

Temperature extremes - Exposure to very hot or very cold temperatures can affect sensor operation and damage the battery.

Battery type - CR-type batteries have lower self-discharge and poor performance at low temperatures, but they are better able to withstand extremely high temperatures.

TPMS sensor efficiency - The Application-Specific Integrated Circuit (ASIC) in older-generation sensors consumed significantly more energy than in current models.

Battery capacity - Capacities typically range from 350 mA to 560 mA across the industry.

Sensor battery diagnosis

It’s not always easy to assess the actual condition of a sensor's battery unless it has already failed! When that happens, the sensor stops transmitting and sets off the vehicle’s malfunction indicator lamp (MIL). A weakened battery can result in sporadic TPMS operation. Some TPMS scan tools have a battery status check, which can help identify a battery with reduced voltage.

Low-temperature troubleshooting

Not all TPMS sensor transmission issues are battery-related. Cold temperatures can create a frustrating TPMS ‘Christmas tree’ intermittent light effect, from a low tire pressure telltale to a system MIL or a back-to-back combination of the two. For example, the season's first frost or a big drop in overnight temperatures can set the stage for this scenario. When temperatures drop, so does pressure, which can trigger the low-tire-pressure telltale. That’s why it’s important to maintain proper placard pressure at all times, especially with the change of each season, when temperature fluctuations are most likely. Extremely low temperatures can further cause the sensor battery to become inoperable, thereby illuminating the MIL.

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If a customer comes in for new tires and a bad or weak sensor battery is detected, consider recommending the replacement of all four sensors while the tires are off the vehicle. This will increase the initial overall cost, but will save the customer a lot of hassle and future charges for a second mounting and balancing, as well as the frustration of not being warned ahead of time.

A TPMS warning light that illuminates solid and remains solid usually means that one or more of the tires has low air pressure and needs to be inflated to the correct placard pressure.

However, a light that flashes for 60-90 seconds and then illuminates solid is signaling that there is a problem with the TPMS system. It is very likely that one or more of the sensors are not communicating with the vehicle. This can be caused by a variety of issues. The flashing light can mean the sensor is damaged, missing, or has a dead battery and needs to be replaced. It can also mean that an incorrect sensor is installed in the tire.
To make sure you service the TPMS systems properly, you need to troubleshoot these potential issues until you find the culprit. Here are some additional tips to keep in mind when your customer comes in for service:
Check the Telltale/MIL every time a customer's vehicle enters your service bay and document the presence of any illuminated or blinking light before performing any work.

Don't forget to inspect the spare if it is equipped with a TPMS sensor.

While servicing TPMS, visually inspect stems, hex nut, seal, and cap.  The recommended best practice is to replace with new service kit.

Always inform the customer of the benefits of TPMS, regardless of whether it presents a sales opportunity or not.

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