Auto Service World
Feature   September 1, 2012   by Jim Curry

KNOWLEDGE BUILDING: TAPPING INTO TPMS


Many Canadian jobbers are choosing to run and hide rather than seek out the burgeoning tire pressure monitoring system market (TPMS). These “hiders” are running away from this lucrative market over fears of a complicated and costly inventory system. However, thanks to the advent of programmable sensors, this fear is no longer valid.

Today, the vast majority of vehicles in Canada are equipped with direct TPMS. These sensors accurately monitor tire pressure as well as temperature, and continuously relay this information via radio signals to the vehicle’s electronic control unit (ECU).

The TPMS radio signals operate on one of two frequencies: 315MHz or 433.92 MHz. In order for a sensor to communicate, the ECU and the sensor must be on the same wavelength.

The direct TPMS sensor is comprised of a body and a valve. The body of the sensor houses a pressure sensor, a temperature sensor, measuring and control electronics, and an antenna, all energized by a sealed-in battery. A microchip converts this information to a radio frequency so that it can be sent via the antenna to a receiver, which then channels this data to the ECU. The valve found in most direct TPMS is either a clamp-in or a snap-in style.

The valve is the most common source of problems in TPMS sensors, because it is vulnerable to mechanical damage as well as the rigours of our Canadian winters, where road salt takes its toll on exposed metals. This is never more apparent than when metal valve caps corrode and become fused to the threads of the valve. Another issue is galvanic corrosion, which is the reaction (arcing) of unlike metals that are in close proximity. Metal valve caps on a thread of different metallic composition spells disaster as they fuse together. Always use a plastic cap with seal on TPMS sensor valves.

The valve core is also a point of concern, as the incorrect metal here can also lead to galvanic corrosion. Electrolyzed nickel-plated valve cores are recommended; be sure to use a valve core torque tool (4 in-lbs.) to properly install cores. Proper torque will also minimize the chances of leakage around the core.

With snap-in valves, there is usually a screw that holds the TPMS sensor body to the valve, and this should be secured using a properly calibrated torque screwdriver tool set at 11.5 in-lbs. If this is over-torqued, then there is a chance that the sensor body housing can be cracked—an expensive error! If under-torqued, then there is a chance of air leakage or the sensor body working loose with time.

Clamp-in valves are common on several different brands of TPMS sensors. Here, the body of the valve is usually made of aluminum, along with a plastic washer, metal washer, nut, and plastic cap. A ¼” drive torque tool in combination with an 11mm- or 12mm-deep socket is recommended for applying the correct torque to the nut. The proper torque often varies depending on the make of vehicle, so consult the TIA Relearn Chart or Mitchell TPMS Systems Guide for correct specifications.

It is strongly recommended that any time a tire is taken off the rim, all of the valve components are replaced. Have your sales team educate your customers on how inexpensive TPMS service repair kits are. Valve components will deteriorate over time, and this service will be appreciated by the customer. The last thing that anyone wants is the constant annoyance of a slow leak in a tire, which can be fatal if left unchecked. If the TPMS sensor cannot be serviced, then it must be replaced with a new TPMS sensor.

With over 300 different OE sensors on the market, a jobber would have to stock at least 1,200 units to properly service the market. This is a huge investment in inventory and inventory management, not to mention the financial investment required. However, today there are several manufacturers that have reduced this monstrosity of OE sensors down to only two aftermarket-programmable sensors.

Some of these manufacturers are claiming 95% coverage of domestic and 85% of imports with their programmable TPMS units. However, before choosing a system to add to your business, ensure that top-selling makes like Honda, Hyundai, Kia, Mazda, Nissan, Toyota, Volvo, and VW, to mention a few, are covered by their sensors. Many programmable systems cover North American makes plus some imports, which need to be supplemented by OE sensors to cover the complete vehicle market.

In order for a replacement sensor to be installed, the technician now needs to know four key facts: the make, model, year, and the ECU program (relearn) procedure for the vehicle.

Some makes, like the Chrysler 300, are auto-relearn; some, like the Chevrolet Impala, are manual relearn, and others like the Toyota RAV 4 require a properly formatted scan tool connected to the OBD-II, such as the ATEQ VT55 OBD-II or the Bartec 400, to mention just two in the market.

A big advantage of the programmable TPMS sensor is that the technician himself can now program the sensor in just a few seconds. This is a huge savings in time, allowing more vehicles to be serviced in a day.

Another feature of some programmable TPMS sensors is that the ID number may be copied from the failing sensor and pasted into the programmable unit. In this situation, the ECU has no problem accepting information transmitted from the new sensor as the original ID number is maintained—no time-consuming and costly relearn stage where it is required.

Savvy jobbers across Canada are now finding a new stream of revenue without the old frustration of the TPMS market. Progressive jobbers are marketing activation tools (with scan tool capabilities) along with programmable sensors, ECU programming tools, service parts kits, torque tools, and TPMS hand tools.

In fact, a few jobbers have expanded their business to program sensors in-house for delivery to shops that may not have the volume to purchase their own programmable package. Some of the leading TPMS supply companies have everything that is needed to be in the TPMS game, and a few even offer training for your sales team as well as for your customer’s technicians.

The TPMS market is expanding each year as an increasing number of new vehicles are OE-equipped with TPMS, and this, coupled with older TPMS sensors needing to be replaced as their batteries wear out, creates opportunity.

As we enter into the winter tire season of 2012, now is a good time to seek out the TPMS aftermarket program that is best to serve your customers. TPMS is not going away, so let’s enjoy the benefits of the business that we are provided.

Jim Curry is account manager for Veritech Mfg. & Wholesale Inc. which represents the 31 Inc .SmartSensor line of TPMS sensors.


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