As you know, tire pressure monitoring systems (TPMS) have been mandatory on new vehicles since 2008. Servicing these systems involves sensor replacement, proper programming and relearning. However, there are a number of common misconceptions and misunderstandings of how some of these systems operate, especially regarding diagnosis, inspection, handling and vehicle-specific procedures. In this article, we’ll share advice and tips regarding TPMS service.
Likely the leading cause of system failures lies with the condition of the sensor batteries. Sensor batteries are expected to last around six to 10 years, with newer sensors lasting longer due to battery improvements.
The rule of thumb is that once a single sensor goes bad, it’s likely that the others are soon to fail as well.
Make this an educational opportunity for the customer. Explain that sensor batteries have a finite lifespan. Let them know that it’s likely time to replace the other sensors. Otherwise they may need to return to the shop once another battery dies.
Always give them the option of changing them now or letting them know that they will likely need sensors in the not-too-distant future.
Replacing all the sensors at the same time avoids having the customer face another tire/wheel disassembly, remount and balance in the near future simply due to dying or dead sensor batteries.
In addition to the ability to perform programming and relearning, TPMS scan tools are available that allow the technician to read individual tire pressure and individual sensor battery condition on-screen, alerting you of low/bad battery state.
Not the batteries?
Other issues can arise that have nothing to do with sensor battery life. One or more sensors may have trouble getting the signal through to the module, which could be a damaged antenna or a wiring issue, or a bad module.
EMI (electromagnetic interference) also can cause issues that disrupt the TPMS signals, such as another wiring harness running too close or touching the TPMS harness, similar to an engine misfire when (depending on the application) two spark plug wires run against each other.
Depending on the design of the vehicle’s electrical system, keyless entry systems also can present problems if TPMS signals run through the keyless entry system, where a keyless system glitch can in turn prevent the correct TPMS signals from communicating properly.
Don’t guess on torque!
This basic service procedure is critical and cannot be over-emphasized. TPMS sensors can easily be damaged by improper tightening of stems, valve cores and/or caps. Seriously... this is no joke. Tightening “until it feels good” simply doesn’t cut it.
All sensor and sensor service kit makers provide torque specifications for core to stem, stem hex nut to wheel and replacement stem to sensor installations.
When a specification calls for 40 in.-lbs., for example, you must use a quality, and properly calibrated, torque wrench that will release torque at 40 in.-lbs.
If you don’t want to use the correct tools and follow the correct torque specs, you shouldn’t be servicing TPMS. Since TPMS sensors require relatively light torque specified in inch-pound value, you need torque-application tools that are specifically designed for these applications.
You can certainly source these from a major tool supplier, but obtaining specialty TPMS torque tools is best done through your supplier of TPMS sensors, since they offer torque-application and specialty tools that are specifically designed for TPMS service. Even pre-set 4 in.-lbs. valve core torque wrenches are available.
We can’t over-emphasize the need to follow correct tightening values. The specified torque values must be followed to avoid valve, core and or sensor damage.
TPMS sensor-related torque values are based on dry-thread torque. Do not apply lubricant to any threads, as this can reduce friction during tightening and can result in unintentional over-torquing.
Tips from AirTech TPMS
There are no TPMS shortcuts. Following are steps to follow when troubleshooting TPMS.
TPMS dashboard icon: solid or blinking? A solid icon indicates low or high tire pressure, or vehicle relearn required. A blinking light indicates a TPMS system error. This could indicate a wrong or dead sensor, or relearn required.
Confirm if the vehicle is equipped with a spare wheel/tire assembly, and confirm if the spare has a sensor.
1. Inflate all tires to match the vehicle placard (including spare, if so equipped). Start the engine. If the warning light is still on, some vehicles require a short drive period. If tire pressure is not the issue but the light is still on, go to Step 2.
2. Scan all sensors with a TPMS tool. Verify that all sensors are functioning. If you can’t obtain correct data from a sensor, the battery may be dead. Write down tire position and the last 5 digits of the sensor ID. Verify that there are no duplicates. If you know the sensor brand, try to modify the sensor ID.
3. Perform a valid relearn. Be sure to follow the specific relearn procedure for the vehicle. There are many sources of abbreviated procedures for a specific year/make/model, but some models may differ. The wrong relearn procedure simply won’t work.
Tips from ATEQ TPMS
To avoid issues with your TPMS sensors, be sure to take the proper precautions to keep the sensors functioning properly. Some common practices include:
– Avoid flat tire repair sprays. Some brands display “safe to use with TPMS sensors.” However, the glue can stick to the sensor and prevent it from working properly.
– Avoid over-torquing the TPMS valve stem nut. This can easily break the sensor stem.
– When cleaning the TPMS sensor port during inspection, don’t allow any sharp objects to puncture the diaphragm, as this can damage the sensor.
– For clamp-in sensors, always use new rubber seals between the sensor and the wheel to prevent sensor damage or leaks. For example, never re-use grommets or O-rings for clamp-in sensors. They develop set dimensions that eventually become permanent to the TPMS sensor.
– When replacing a snap-in sensor, always replace the valve.
If you cannot read tire pressure information from the vehicle using your TPMS tool, first determine which TPMS light is on... a malfunction indicator lamp MIL or telltale light. The MIL will blink when the ignition is turned on, indicating a failure of operating the TPMS, such as a dead sensor. The telltale light will remain solid to warn the driver when their tire pressure is below 25% of the placard pressure.
Next, determine if the vehicle has a direct or indirect TPMS. Direct TPMS uses TPMS sensors inside the wheels to report pressure data to the vehicle’s ECU in real time. Direct systems include domestic, Asian and European vehicles. An indirect system uses an ABS to monitor the speed of the wheel and communicate with the ECU. Indirect systems include some Asian and European vehicles.
There are ways to determine whether the vehicle is equipped with a direct or indirect TPMS.
– Use your TPMS tool to look up the make, model and year of the vehicle to determine the relearn procedure. It should list whether your system is a direct TPMS (auto, stationary or OBD II relearn procedure) or indirect TPMS.
– Refer to the Tire Industry Association (TIA) or your service information provider relearn chart to determine the type of system.
– Demount the tire to verify which system you are working with. If there is no TPMS sensor in the wheel, and the vehicle is 2008-present year, the vehicle has an indirect TPMS. If the vehicle is older than 2008, indirect TPMS were available in many vehicles, so be sure to visually inspect the valve.
A TPMS sensor valve has a visible “shoulder” shape on the valve, where a valve with no TPMS sensor attached does not have the same shape and is easier to physically move back and forth. If you are working with a direct TPMS and your TPMS tool still does not display the vehicle make, model and year, you may want to update your tool to the latest software version.
Tips from Autel Intelligent Technology Corp.
One of the most common TPMS tool feature purposes that customers don’t understand is the difference between a sensor relearn and a sensor program procedure. They think programming and relearn are the same thing, but they are two different procedures that offer different benefits.
Users don’t understand the fundamental differences between the features and why one is more useful than the other.
The ability for a sensor to provide both options is an important profit saver, but better TPMS tools provide a clear understanding why a relearn procedure saves time and the ability to program a sensor helps shops cut down on their sensor inventory stock.
Tips from Bartec USA
The following information is provided by Scot Holloway of Bartec USA.
As we celebrate the 10-year anniversary of TPMS being a 100% mandate in the U.S., there still remains plenty of obstacles relating to the diagnostics and service of these safety systems.
1. Keeping the TPMS tool up-to-date: Vehicle coverage, new sensors and better features are always coming. Keeping the tool current is very important and can often mean the difference between a happy customer and one that’s talking about you on the internet.
2. Retrieving information from the tool: The collection of critical inspection, diagnostic and vehicle data are now part of the process for some TPMS tools.
3. Length of time to complete TPMS service: We often hear that dealing with TPMS service takes too long, whether it be extra steps dealing with replacement sensors or redundant steps of looking up a customer, knowing the vehicle make, model and year at the point of sale, only to have to set up the tool separately.
4. Changing the recommended inflation pressure: We hear loads of stuff about this topic, mostly whether or not it can be changed, and this remains a significant obstacle. TPMS placard changing is necessary if plus-sizing or “up-fitting” tires.
5. What kind of sensor is inside the wheel? A few years ago, we knew that the vehicle was fitted with OE sensors, but you cannot be so sure today, since the wheels may have been serviced previously. Do you have the proper service kit or tools for the possible aftermarket sensor that’s inside the wheel?
Tips from Continental VDO
Listed here is an assortment of tips that refer to TPMS service, provided by Sean Lannoo, sales technical training specialist, and Lindsay Smith, product manager.
– Refer to the placard pressure when inflating tires, not the max pressure listed on the tire sidewall.
– Use the 10th digit of the vehicle VIN to identify vehicle model year, not the build date.
– Make sure that the shop has an assortment of service kits in-house for easy access.
– Protect the wheel when pulling the valve stem through. More rubber stem sensors are used on aluminum wheels.
– Follow the specific vehicle relearn procedure:
- Some vehicles must be driven immediately after relearn for a length of time at or above a specific speed.
- Some vehicles must sit for a predetermined time after relearn before driven for a length of time at or above a specific speed.
- Some vehicles require sensors to be triggered a second time after relearn.
- Be sure to keep your TPMS tool fully charged and updated with the latest software.
- When triggering sensors, it is possible that you might have to rotate the tire so the vehicle can receive the RF (re: interference from body panels, modules, brake components and steering/suspension components).
- If one sensor battery is dead, the others are likely close (if all were installed at the same time).
- Always change service kits to prevent ghost leaks and comebacks.
- Some GM vehicles must be put into Service Mode in order to access the relearn mode.
- Newer Fords have Auto-Relearn capability.
- Newer Fords have a tire rotation relearn and a sensor replacement relearn. The tire rotation relearn will not learn a new sensor ID.
– Sensor battery life typically lasts seven to 10 years. These batteries are not replaceable as they are fully enclosed in the sensor body. Attempting to replace the battery can compromise the integrity of the sensor assembly, ultimately leading to system failure.
– Aluminum stem corrosion must be addressed. Regularly checking the condition of the valve stem and replacing the service kit hardware during every tire service are ways to reduce the risk of corrosion issues. It is also important to use only hardware that is approved for use with TPMS sensors. For example, older non-TPMS valve cores that are made of brass cannot be used with TPMS valve stems. Nickel plated valve cores must be used in order to prevent corrosion.
Tips from Dill Valves
The information here on aluminum stem corrosion is provided by Tyson Boyer of Dill Valves/Dill Air Control Products.
Aluminum is a lightweight alloy but is susceptible to long-term corrosion, similar to other aluminum vehicle components. Aluminum tire pressure monitoring valves must be inspected during every tire-related service, as they may corrode over time, leading to potential failure.
While some OEM sensors cannot be retrofitted with a new valve, note that some OEM aluminum valve stems are not permanently attached to the sensor and may be serviced without the need to replace the sensor. These two-piece sensor and valve stems must be replaced during tire service or replacement when corrosion is evident, allowing the continued use of a good sensor. Dodge, Chrysler, Jeep, BMW and VW, as examples, feature sensors equipped with a replaceable aluminum valve stem.
Service kits are available that include the valve stem. The valve stem attaches to the sensor body by inserting the valve head from the bottom side on the front of the sensor before installing into the wheel. The hex nut is then installed and tightened to a torque value of 58 in.-lbs.
The most common type found on makes such as Audi, BMW, Mini and VW is installed into the wheel first in order to obtain the proper alignment of the sensor. Using a mounting pin to hold the base of the stem, tighten the hex nut to a value of 40 in.-lbs. Next, attach the sensor to the base of the stem and torque the screw to 35 in.-lbs.
Kits are available that include a locking hex nut that features a shear ring internal to the nut that will shear off as the hex nut is tightened short of full torque value, ensuring that the valve stem and sensor are locked together. The ring is sheared prior to reaching 35 in.-lbs., after which the nut is then final tightened to 35 to 40 in.-lbs.
Some OE designs feature an easy to replace valve stem. The stem should drop into the clip at the narrowest section of the threads, and then pulled into place. Once you install it into the wheel, align the flat surface of the washer to the underside of the sensor body.
Slide the rubber grommet on the stem with the angle edge up and straight edge down. Install the hex nut while adjusting the valve to the wheel angle and torque it to 71 in.-lbs. If the grommet and washer are of the one-piece design, there will be no flat side so alignment is not important. This simple to install OE stem is found on numerous European, Asian and domestic vehicles.
Kits for Dodge six-wheel dually applications with alloy wheels may feature inner duals equipped with a rubber valve stem. During replacement, be sure to torque the sensor to the valve stem first with the hex screw at 12 in.-lbs. After inserting into the wheel hole, install the nut and torque between 80 and 125 in.-lbs.
Always verify the proper part for the application you are working on before installing and follow all instructions that are provided with replacement TPMS components.
Editor’s note: It is critical to pay attention to the specified torque values listed for any given TPMS sensor. Under- or over-tightening can easily result in leaks and/or sensor damage. NEVER guess at torque value. Be sure to carry the inch-pound torque wrenches that are dedicated for TPMS service.
Editor’s note: Do not be tempted to apply any type of lubricant to aluminum stems or hex nuts or any threaded connection on the sensor. There will be no advantage in terms of reducing corrosion, and the application of thread lube may result in incorrect torque. All TPMS sensor threaded torque values are based on dry threads.
Use of a lubricant can easily result in over-torquing.
Tips from JS Products Inc.
The following information was provided by JS Products’ Michael Christopherson.
Toyota and Lexus
Toyota and Lexus vehicles commonly have a sensor in the spare that will trigger a TPMS light. Always check the spare when looking for a source for the warning light. Toyota and Lexus vehicles may have a Set 1 and Set 2 button. This is so customers can run winter tires. Sometimes the button is pushed by mistake, generating a code. It may be necessary to push the switch to turn the TPMS light off.
On Toyota and Lexus vehicles there is commonly a “set” button that reassigns the tire positions when tire/wheel assemblies are rotated. If a new sensor is added to the system and the button is pushed before a scan tool relearn process, it will lock the system. The system will need to be unlocked with a scan tool and relearned with a scan tool before the system will operate normally again. In the case of a Set 1 and Set 2 system, the system will need to be relearned twice...once for Set 1 and once for Set 2, including the spare.
If tire/wheel assemblies are taken from a different year of a similar model vehicle, improper sensors may learn to the vehicle, but may report the wrong tire pressure. Correct sensors must be installed. For programmable sensors, the correct year, make and model must be input.
Some aftermarket programmable sensors “lock” after the tire has been inflated. It is important to program the sensor before installing the sensor to the rim. After airing up and installation, the relearn process can be followed normally.
Many technicians get confused as to the difference between “programming” and “relearning” the TPMS sensors. Programming is when a programmable sensor is assigned a protocol and ID previous to installation. Relearning is a process of the vehicle system recognizing the IDs and the positions of each wheel.
Newer Ford vehicles can be manually learned or they may auto-learn wheel positions. With auto-learn, the wheels may learn to the wrong locations. This is especially true with aftermarket sensors. A best practice is to manually learn wheel positions.
Kia and Hyundai
Before installing programmable sensors in Kia and Hyundai vehicles, verify that the sensor is applicable to the system, as there are High Line and Low Line systems. High Line systems will display the pressure at each wheel.
Low Line systems feature a TPMS lamp that indicates a problem in the system. The applicable sensors are different even in the same model year.
Certain GM vehicles require the use of the key fob or factory tool to put TPMS into the learn mode. Make sure the customer has the key fob and verify that it is broadcasting before starting service.
Tips from Schrader/Sensata Technologies
The following information is provided by Jacki Lutz at Schrader/Sensata Technologies.
“Our call center’s number 1 call is always concerning the difference between programming vs. relearning a sensor,” says Lutz.
“Some of our customers don’t understand the difference and when instructed to program a sensor, they try to relearn the sensors, causing errors.
“Our number 2 call is in regards to relearning the vehicle, in terms of how to relearn the vehicle and the importance of following the unique application instructions to every last detail.”
Programming and relearning
Editor’s note: Our intent is not to promote any specific brand of sensor. However, following is an example of the steps required to program and relearn an aftermarket programmable sensor.
Lutz offers the following advice.
Programming: Depending on the aftermarket brand and model of sensor, sensors may be pre-programmed or may be initially blank and must be programmed to the specific make, model and year vehicle, with the use of a programming tool.
The TPMS tool programs the sensor with the vehicle-specific protocol so that the sensor will communicate with the vehicle’s receiver. The sensor can either be created with a new ID or it can be copied from an existing sensor and programmed onto the new sensor.
Note that other sensors are available that are pre-programmed and require no in-shop programming and are ready for installation and relearning.
Various sensor designs are available from aftermarket manufacturers.
Relearning: A relearn is required whenever a new sensor ID is introduced or when the wheel/tire assemblies are rotated.
The vehicle’s ECU records the sensors (four or five, depending if a spare is in the vehicle).
This allows the unique sensor IDs are correctly recognized by the vehicle’s ECU. On vehicles with a pressure-by-location function (where the system lets you know which tire is low), the ECU is now ready to display the correct wheel location of each tire’s pressure. Using a TPMS scan tool, you’re able to relearn the sensor IDs to the vehicle’s ECU.
The tool will wake up (ping) each sensor, one at a time (LF, RF, RR, LR, spare) and store individual sensor IDs.
Tips from Standard Motor Products Inc. (SMP)
Today’s motorists don’t trust what they don’t understand, which is why there’s such a great opportunity for service technicians to help with TPMS. Common questions that need answers include, “What sensors should I use — OE or universal?”, “When should I clone a sensor and why?”, “When should I perform a ‘re-learn’ on a vehicle?”, “What is the best scan tool to use?”, and maybe the most critical question, “When should I talk to my customer about TPMS?”
If you want to position your business as an expert in this service category, you should be prepared to talk TPMS. Here are a few expert tips:
1. First perform an inspection
When a customer visits your repair facility for a tire replacement, tire rotation, or TPMS-related concern, your first action before performing any work should be to obtain their information and conduct a quick system check. This extra effort up front will help you explain potential damages later and, most importantly, ensure that your customer is pleased with their service experience. Here’s what to do:
To start, perform a bulb check by turning the ignition key from OFF to RUN. All of the warning lamps on the dash should illuminate and go off in approximately 5 seconds. If not, there’s an error.
2. Know the difference between a solid and flashing light
If during your bulb check the warning lamps don’t illuminate and go off in 5 seconds, here’s what it means:
Error #1: Low Tire Pressure Telltale (Solid Light)
If the light remains illuminated, the TPMS system is indicating that one or more tires has an inflation error. Some vehicles (if the previous service provider performed a relearn) provide an additional message indicating the position of the fault. For low tires, check the placard on the vehicle to find the recommended pressure, fill up the tire accordingly, make sure the warning light goes out, and repair the cause of the leak.
Error #2: Malfunction Indicator Lamp (MIL) (Flashing Light)
If the light flashes for 60 to 90 seconds during a bulb check and then stays solid, there is a fault with the TPMS, such as the sensor, receiver, or module. Use a tool to retrieve Diagnostic Trouble Codes from the vehicle, or use a TPMS tool to read each sensor.
For more information on these procedures, refer to the videos on our YouTube channel at www.youtube.com/standardbrandparts.
3. TPMS relearn
The final step of any tire or TPMS-related work should be a TPMS relearn. This step will ensure that the correct ID numbers are stored in the proper location. In the event of a future fault, the relearn will indicate the correct position to the driver and future repair technician.
4. Keep an inspection sheet
Once the work is complete and the money is collected, it’s helpful to have an inspection sheet to show the customer. The inspection sheet should document as much information as possible, including customer information, TPMS ID numbers, DTCs, and more. Also, you can use the inspection sheet to inform the customer that 1.) a relearn was performed, and 2.) they can feel safe knowing their TPMS system is functioning and reporting properly. In the end, this simple communication can go a long way toward ensuring a successful TPMS repair and a happy customer.
5. Don’t forget the service kit
The Tire Industry Association (TIA), U.S. Tire Manufacturers Association (USTMA), and the Motorist Assurance Program (MAP) require that every time a tire is removed from the wheel you should replace TPMS service parts such as the valve stems, seals, washers, nuts, valve cores and caps.
Advice and tips from Xtra Seal/Group 31 Inc.
The following advice and recommendations are offered by John Rice of Group 31 Inc.
All sensors must be programmed prior to installation. This would apply to universal programmable sensors as well as selectable programmable sensors.
All sensors must have a unique ID (no two can be the same on the same vehicle). Many universal programmable sensors allow the user to create a copy/clone of the OE sensor, and it’s important after the OE sensor is copied/cloned that no two sensors with the same ID end up being installed on the vehicle.
Many Audi, VW, Mazda and Honda vehicles feature indirect TPMS. Vehicles equipped with indirect TPMS do not have sensors in the wheels, therefore no sensor will be detected when trying to scan/activate/wake-up the sensors.
Typically, the only service required is to inflate to the proper pressure and reset by pressing a reset button.
Not all vehicles relearn the TPMS by simply driving the vehicle after TPMS service. Actually, only about one-third of all vehicles are Auto Relearn. The remaining systems are either Stationary Relearn or OBD II Relearn.
Keep your TPMS tool(s) updated. It’s important to update your tools whenever updates are available.
Updates can include new vehicle applications, new features, software fixes, etc. By keeping your tools up-to-date you’ll always be ready for the next vehicle that enters your shop.
Some TPMS tool manufacturers charge an annual fee (typically $200-$300) for updates, but there are some TPMS tools available with lifetime free updates.
Keep sensors in stock. It is inevitable that the customer needing a replacement sensor shows up at 5 p.m. on a Saturday, and the last thing you want is to have to wait for your local parts store to deliver a sensor, assuming that they are even able to do so.
With universal/programmable sensors, you can stock one to two sensors and be covered, with no huge inventory investment.
Don’t forget to replace the TPMS service kit. OEMs recommend replacing the TPMS sensor components (rubber valve for a snap-in style sensor) and core, cap, grommet, etc., if it is a clamp-in style sensor during every tire service (including installation of new tires, new wheels, tire repair, etc.).
These special sealing elements are designed for a single use and should be replaced periodically to ensure a proper seal between the sensor and wheel. Several distributors offer service kit assortments covering many vehicle applications.
There are even TPMS valve assortments that cover the ever-growing number of replacement rubber TPMS valves.
Note that a valve-mounted sensor (snap-in or clamp-in) can be used to replace a banded sensor.
NOTE: Ford has two relearns available, one for tire rotation which uses the hazard switch to initiate the relearn (listed in the owner’s manual), and another relearn when a new sensor has been introduced on a vehicle and uses a sequence of steps to put the vehicle into relearn mode by cycling the ignition switch (not listed in the owner’s manual).
Another tip: When one or more of the tires are significantly underinflated, the TPMS indicator will be solid at start-up. If a malfunction occurs (typically a sensor issue), the MIL will blink for 60 to 90 seconds and then go solid.
The first step in properly diagnosing a TPMS issue is to note what the TPMS light/MIL tells you at start-up.
Upgrading tires and changing placard value
Apparently, the process is quite simple. For direct-TPMS, using the appropriate scan tool that allows this reprogramming function, select the mode that enables tire pressure value resetting (the steps will vary depending on the make and model of tool), change the factory OEM values to the new desired values, again following the prompts on the specific tool in use.
Once the system has been reprogrammed to alert based on a new inflation pressure value, fill out a supplemental tire cold inflation pressure placard and attach it near the factory tire placard. Include the new tire size, load rating and new cold inflation pressure.
It’s common for many customers to switch to dedicated winter tires for their region’s cold/snow weather period. Obviously, we have several options. The original or “summer” tires may be demounted and the winter tires of the same size may be mounted to the same wheels.
Since a tire service is being performed, it’s best to take the opportunity to install new TPMS sensors and service replacement parts to ensure proper sealing and battery performance. The sensors may be pre-programmed or need to be programmed (depending on make and model of the sensors).
The winter tires should feature the same overall diameter as the OE tires in order for the ABS to function, so the winter tires may require the same inflation pressure as the OE tires. If not, the inflation pressure would have to be reprogrammed to the TPMS ECU.
Once the wheel and tire assemblies have been installed to the vehicle, the sensors need to be relearned.
However. some customers prefer to run different wheels with their winter tires, for two reasons: to save the OE or aftermarket alloy wheels from salt, ice and slush, and for the ability to run a narrower tire with a taller sidewall, which is better suited for snow and ice traction and handling as compared to a wider tire with a shorter and less-compliant sidewall.
Tire size would be based on finding a size that is equal or near-equal to the original tire overall diameter in order to provide the ABS module with the proper overall diameter and rotational distance, while being narrower and still providing a load index that is suitable for the vehicle.
For example, a vehicle is equipped with OEM alloy wheels and 205/55R16 tires. This size tire features an overall diameter of 24.9 inches. The customer wishes to move to steel wheels and a narrower winter tire with a taller sidewall.
One choice would be 15 x 6 or 6.5-inch wheels with 195/65R15 winter tires, which have an overall diameter of 25 inches, but with a narrower section width and taller sidewall.
In order for the TPMS to remain operational, TPMS sensors would need to be installed to the new steel wheels, using sensors that have stems compatible with the valve holes in the wheels. Once the sensors are programmed (along with any change to inflation pressure that may be needed), the assemblies are installed to the vehicle and relearned.
DO NOT be tempted to install any wheel with no TPMS sensor on any vehicle that was originally equipped with direct TPMS. The National Highway Safety Administration’s interpretation of the Motor Vehicle safety Act prohibits service providers from installing aftermarket tire and wheel assemblies without working TPMS sensors.
Depending on the state, the TPMS might not need to be functional in order to pass an inspection, but a shop is not allowed to omit the sensors on a vehicle that was equipped with TPMS.
From a purely functional aspect, if the winter wheels are not equipped with TPMS sensors, no sensor signal would be sent to the ECM, which will result in no system monitoring of tire pressure, and the TPMS warning light to remain on during the months of winter tire use.
However, a shop is not allowed to omit the sensors.
TPMS module replacement
After replacing modules that contain TPMS data, it is required to relearn TPMS data. It’s interesting to note that on Ford vehicles, proper module programming and TPMS relearning is required.
The vehicle’s dome lamp will flash until all needed programming and relearning is complete.
Tip for sensor programming
The best practice is to program sensors away from where other sensors in your inventory are stored. Multiple sensors might be programmed by mistake.
Typically, a flashing TPMS light indicates a TPMS fault and a solid light indicates a tire pressure issue. To make sure that there is not a system fault, cycling the key is necessary. Once driven for a time, the flashing light will go solid.
Cycling the key will reset the system and allow for either a solid or flashing light. It’s best practice to relearn the TPMS anytime the wheels are removed.
You never know if the “last guy” rotated the wheel/tire assemblies and did not perform a relearn.
Once one or more TPMS sensors have been replaced, or a service such as tire/wheel rotation has been performed, a relearn procedure is likely required.
There are three basic types of relearns, depending on the make, model and year vehicle. These include auto-relearn, stationary relearn and OBD II relearn.
Auto Relearn applies to vehicles that are designed to learn sensor IDs without the need for a TPMS tool. Once the service has been performed, the vehicle simply needs to be driven for a predetermined amount of time in order for the system to reset.
Depending on the vehicle, this may require as little as 5 minutes to as long as perhaps 20 minutes. However, to prevent wasting your time, it’s advisable to first use a TPMS tool to trigger each sensor to verify that the sensors are functioning properly.
It should be obvious that all tires must first be inflated to the placard’s recommended pressure.
A Stationary Relearn allows sensor IDs to be transferred to the vehicle ECU while in the shop. This typically requires a TPMS tool or an OBD II scan tool.
An RF signal communicates with the ECU to inform the computer as to the location of each sensor wheel position.
According to ATEQ, an example is the 2014 Ford Escape that features a standard ignition. Inflate all tires to the specification, turn the ignition off, press and release the brake pedal, cycle the ignition off to run three times, finishing with the engine in the run position. Next, press and release the brake pedal again, and then turn the ignition to the off position.
Once again, cycle the ignition from off to run three times, finishing with the engine in the run position. At this point, the horn will sound twice (at least, it should).
Use the tool to activate the left front sensor, at which point the horn should sound once. Repeat this process for the right front sensor, followed by the right rear sensor, followed by the left rear sensor.
The sequence must be followed properly (LF, RF, RR, LR).
The OBD II Relearn requires a TPMS tool to transfer the new sensor IDs directly to the vehicle’s ECU.
With the tool connected to the OBD II port, each sensor is scanned, following the prompts on the tool.
The sensor IDs are then transferred to the ECU. Most Asian and European vehicles currently require the OBD II relearn procedure.
Referring to a 2011 Toyota Camry as an example, the procedure is as follows:
1. Inflate all tires to specification.
2. Read all sensor IDs using a TPMS/scan tool.
3. Connect the tool to the OBD port.
4. Reset the ECU using the tool.
5. Turn the ignition off, then to the on position.
6. Drive the vehicle at a speed of about 12 mph for about five minutes.
Again, this is merely one example. Always follow the procedure provided by the auto maker’s service manual or the instructions provided by the sensor and/or tool maker.
GM keyless entry/TPMS problem
Several GM models require the use of the keyless entry remote fob in order to perform a TPMS relearn. If the keyless entry system malfunctions, TPMS relearn may not be possible, as well as the dashboard information center showing TPMS faults.
A cause of the issue may be related to allowing the vehicle’s battery to drain. After charging the dead battery, the issue may be presented.
Apparently, the dead battery problem may have caused the RCDLR (remote control door lock receiver) and RKE (remote keyless entry) transmitter to not function after the serial data bus has gone to sleep.
The RKE transmitter rolling codes may become out of synch with the RCDLR, resulting in intermittent operation of the keyless entry system, poor RKE range and service tire monitor system message.
If the key fob(s) are inoperative and the TPMS is not reading correctly (dashes on all four tire readings), the technician may find DTCs C0775 (low tire pressure system sensors not programmed), C0569 (system configuration error), B3105 (keyless entry fobs not programmed) set in the RCDLR module. The technician may find that the TPMS sensors are unable to be programmed to the vehicle by adding or releasing pressure to the tires while in the TPMS learn mode.
According to GM, you need to reprogram the RCDLR with an updated software calibration using a Tech 2.
Once the module has been re-flashed, it may be necessary to relearn all keyless entry transmitter fobs, reconfigure the tire pressure placards and tire type and relearn all TPMS sensors.
If the Tech 2 cannot establish communication with the RCDLR and the programming event ended with “error,” attempt to reprogram by selecting “remote control door lock receiver with E4399 error....pass thru only.”
However, if reprogramming does not work, the RCDLR module may need to be replaced because it went to sleep and can no longer maintain its information. Another possible glitch with GM systems involves the addition of a two-way remote start option that may have been dealer-installed.
If the customer complains about having a constant or intermittent “service tire pressure system” message, along with key fob range issues and/or remote start issues, check to see if a two-way remote start system has been added.
Possible trouble codes include C0750 (low LF tire pressure), C0755 (RF low pressure), C0760 (low LR pressure) and C0765 (low RR pressure).
Check for the proper placement of the remote start antenna and check for pinched wires between the antenna and the receiver. Antenna placement differs with the vehicle model, so check with the Accessories Installation Manual in the service manual for vehicle-specific antenna placement.
Apparently, a small change in antenna location can drastically decrease the operating range. If the antenna is damaged, it’s available separately. ■
TPMS PARTS AND TOOL SOURCES
Autel Intelligent Technology Corp.
Continental Automotive Systems Inc./Continental VDO
Dill Air Control Products
Huf North America
JDI Dynamic/John Dow Industries
JS Products Inc.
Regitar USA Inc.
Revolution Supply Co./Oro Tek
Schrader-Bridgeport International Inc./Sensata Technologies
Standard Motor Products Inc. (SMP)
Xtra Seal/Group 31 Inc.