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Thread: Tire Pressure Monitoring Systems (can we sticky this please)

  1. #1

    Tire Pressure Monitoring Systems (can we sticky this please)

    Well since Evo X and every 2008 vehicle has TPMS in it I might as well edumacate you guys on this

    A tire pressure monitoring system, also referred to as TPMS, is relatively basic in terms of the number of involved components. The pressure sensor transmitters (one transmitter mounted inside each wheel) monitor inflation data and send a radio signal to the system's antenna and receiver, which then sends a digital signal to an ECU. Note that some vehicles are equipped with one central antenna, while others feature individual antennas in the wheel wells at each corner.

    A direct tire pressure monitoring system -- one in which a dedicated system exists that monitors actual tire inflation pressure -- is generally calibrated to alert the driver when one or more tires have lost at least 20% to 25% of the programmed/recommended inflation pressure.

    In most instances, if a "fault" signal is processed by the ECU, the in-dash tire pressure warning light will illuminate, while if a tire pressure problem is indicated, the warning light will illuminate constantly. If the light blinks, as it does in many newer OEM systems, it indicates a system fault that must then be diagnosed with the proper diagnostic tool.

    It's important to note that whenever sensors are moved to new locations (during wheel rotation, etc.), the individual sensors may need to be re-programmed or re-set in order to maintain correct location information for the system ECU. Otherwise, each sensor may transmit correct inflation data, but the ECU will then assign the pressure data to the wrong corner(s) of the vehicle.

    For example, if a vehicle is equipped with dash information that identifies each specific wheel location, you may see a warning that the left front tire is low, when, in fact, the low pressure problem may be found at the right rear (because the wheels were rotated and the sensors were never re-set).

    TPMS components

    Two basic "styles" of TPMS sensor/transmitters are available: banded and stemmed. (The correct OEM term for the sensor is wheel mounted sensor.)

    Banded sensors are affixed to the inside of the wheel using both a positioning adhesive (peel off) and a band clamp. Stemmed sensors feature the valve stem as an integral part of the sensor. The sensor mounts via the wheel's valve hole and is secured with a mounting nut. Depending on the maker's design, these wireless pressure sensors transmit their data to an ECU using either AM or FM signals, usually in the 125 kilohertz range.

    Five primary sources for OEM tire pressure monitoring systems include Schrader Electronics Ltd., Beru AG, Pacific Ltd., Siemens AG, TRW Automotive, etc. Schrader systems are found on Ford, Chrysler, GM and Nissan/Infiniti applications. Pacific systems are found on certain Toyota (including Lexus) and Honda vehicles. Beru systems are used on Mercedes, Porsche, BMW, Audi/VW and Land Rover models.

    Since the OE transmitters are the stem type, the wheels are designed to accommodate these units (the valve stem hole area is configured for these transmitters). Some aftermarket wheels do not allow the addition of the stem-type transmitter, which makes them suitable for a band (strap-on) type.

    The vast majority of OE tire pressure monitoring systems are stem-mounted as opposed to band-mounted. The primary reason involves diagnostic capabilities. If the sensor is band-mounted and deeper inside the wheel, it's more difficult for the signal to pass to the diagnostic tool, whether the system uses an RF signal or a magnetic signal.

    Stem-type sensors are light, weighing in the neighborhood of about an ounce, so this won't be a problem regarding wheel balance compensation.

    Most direct type pressure sensors are powered by a lithium battery with an expected lifespan of seven to 10 years. Many of them are designed to operate only during or after a 20 mph-plus driving experience. When the vehicle is parked, the sensors are usually designed to transmit pressure only once per hour or so, in order to preserve battery life.

    Who needs a TPMS?

    Are tire pressure monitoring systems really necessary? Some might say that these systems are a waste of money, arguing that if people would simply check their tire pressures on a regular basis, there would be no need for an on-board monitoring system. But, therein lies the rub. Most people don't bother checking inflation pressures, at least not as often as they should.

    Aside from protecting people from their own ignorance, tire pressure monitoring systems do make sense for a number of reasons.

    1. They provide safety. Even for those who recognize the importance of tire pressure and routinely perform a manual check, it's nice to be alerted to a drop in pressure before the tire fails. It doesn't matter whether the drop results from a puncture, faulty valve or chuckhole tear.

    2. They protect run-flat tires. Another example of the need for a TPMS lies in the design of run-flat/zero-pressure tires. Many of the run-flat tires on the market are constructed so superbly that a drop in pressure may not be discernable to the driver. So it's vital to have a system in place that alerts the driver of a low pressure problem in an effort to prevent tire damage and avoid a traffic mishap.

    Regardless of personal opinions on the matter, we really don't have a choice. After Aug. 31, 2007, all new model four-wheeled vehicles weighing 10,000 pounds or less must be equipped with tire pressure monitoring systems. This means that the aftermarket service industry must be able to handle these systems properly and diagnose system problems.

    Indirect systems


    As a relatively inexpensive method of altering the driver to a low tire pressure situation, some OEM vehicles obtain this information not through a dedicated direct tire pressure monitoring system, but rather by using information already monitored by the anti-lock braking system. This is referred to as an indirect TPMS.

    A "low" tire will rotate at a different rate than properly inflated tires (due to a difference in rolling tire diameter); this difference in wheel rotation is sensed by the ABS. A signal is then sent to alert the driver via a warning light. It's then up to the driver to check all four tires to determine which is under-inflated.

    This approach has its problems. Faulty alerts can easily result if the wheels slip on an icy road, or if inside and outside wheels rotate at different speeds during sharp turns, because ABS monitoring interprets a difference in rotation as a low pressure condition. In addition, if all four tires are equally under-inflated, the ABS won't trigger the pressure warning, since all wheels are rotating at the same speed.

    In general, indirect tire pressure monitoring systems are designed to illuminate the warning light when a single tire's recommended inflation pressure has dropped by about 30%.
    Jesse Sez: If you're ever in a midget-tossing contest, always go for the happy midget. It is definitely much harder to toss them when they're unhappy

  2. #2

    Re: Tire Pressure Monitoring Systems

    Tools of the trade

    In order to service any direct TPMS, a testing tool is absolutely required. At the OE level, these calibration/re-setting/diagnostic tools range from hefty hand-held units to large stationary pieces of equipment. For aftermarket use, easy-to-use hand-held testers are readily available.

    A TPMS diagnostic tool has two common uses: re-setting the system and pre-testing the system's operation, which helps determine if a system fault exists. You should perform a system re-set whenever wheels are rotated, or whenever sensors are moved from their original locations on the vehicle. Re-setting accounts for about 75% of the tool's use.

    According to SPX/OTC Product Manager Rob Kochie, a typical scenario involving the need to pre-test is as follows: The owner of a 2005 Corvette (equipped with a TPMS) pulls into your shop in need of new tires. Following the tire service (dismounting, mounting, balancing and installation), the tire pressure warning light is illuminated.

    The diagnostic tool can be employed to determine the fault, which might be traced to a specific sensor that was damaged during dismounting or mounting.

    The confusing aspect of tire pressure monitoring systems today is a result of the proliferation of system designs and diagnostic capabilities. Some systems are more adjustable than others. Some systems require re-setting if battery power is interrupted, while this is not a factor in other systems. Some systems collect data relative to any tire, while others identify specific tire locations.

    Procedures for re-setting also vary among vehicle makes/models/years. Full-size spares (where applicable) are monitored while spares on some models are not.

    In all, there are about 40 to 50 different testing and re-setting protocols in use, which poses a challenge for makers of testing and diagnostic tools. Some service tools are make/model/year-specific, while others are designed to communicate with a variety, if not all, of the various tire pressure monitoring systems.

    Here's one service example: When performing a re-set on a 2005 Corvette, the ignition key is turned to the ACC mode, while two buttons on the remote key fob are pressed and held. Following instructions provided by the testing tool, each sensor will re-set and will confirm the new "learn" by beeping the horn or flashing the lights.

    We simply don't have room here to describe each make/model/year initialization or re-setting procedures. For any given procedure, the steps will be outlined in the vehicle's service manual, or can be obtained through Mitchell1's available data, or by following the steps provided with a TPMS service tool.

    Remember that any direct system's individual wheel sensor/transmitter will feature an ID code. Whenever replacing a sensor (or tire pressure monitoring system ECU), you'll need to record the sensor ID code. Depending on the brand of the sensor, this will appear somewhere on the main body of the sensor.
    Jesse Sez: If you're ever in a midget-tossing contest, always go for the happy midget. It is definitely much harder to toss them when they're unhappy

  3. #3

    Re: Tire Pressure Monitoring Systems

    DISMOUNTING & MOUNTING PRECAUTIONS REGARDING TPMS

    1. Average mounting grommet life on most TPMS sensors is about five years, at which time the grommet must be replaced. To avoid any confusion, replace the grommets whenever the tire/wheel is serviced. However, because these grommet kits are not readily available -- and are expensive -- the Tire Industry Association suggests an alternative service option. "We say if you remove the sensor from the rim, you must replace the grommet," says Kevin Rohlwing, senior vice president of education and technical service. "But if the customer chooses not to replace the grommets, the assembly can be serviced with the sensor in place."

    2. Always follow the vehicle service manual's tightening specification for TPMS sensor nut torque. Not all stem-type sensors require the same torque value!

    3. Do not attempt to install an OEM stem-type TPMS sensor onto any wheel that is not specifically designed for this application. This includes steel wheels, and any alloy aftermarket wheel that is not designed for the sensor.

    4. Only replace valve stem cores with the original or an original replacement. Using a core that is not nickel plated can lead to corrosion and pressure loss (valve stem sensors are often made of aluminum with a special coating, and require a nickel-coated core to prevent corrosion).

    5. Before breaking the tire bead and in order to avoid damaging a stem-type TPMS sensor during dismounting, fully deflate the tire, remove the mounting nut and gently push the sensor into the tire (the tire/wheel should be in a vertical position, with the sensor positioned at the 6 o'clock position during drop-in to avoid the sensor hitting the wheel). Once the outer bead is unseated, reach into the tire and retrieve the sensor to prevent further potential damage.

    6. To prevent moisture and dirt contamination, always reinstall the original type valve cap, which will feature a small sealing O-ring. This alsi includes those chrome valve stem caps which are made of a brass alloy. The corrode at a different rate and can fuse with the stem causing the stem to break. Mazda, GM, Ford have TSB's regarding about this.

    7. When re-installing a stem-type TPMS sensor, secure the valve to prevent rotation during nut tightening. Once tightened, the gap between each side of the sensor body and the wheel surface should be equal.

    8. Never allow the tire machine's mounting head to touch the sensor.

    9 Even if no telltale stem-type valve is visible on the outside of the wheel, never assume that no TPMS sensor is present.

    Tip: If a color-coded washer is visible on the outer stem area, this is a clue that a band-mounted sensor is in place.

    10. Once the stem-type TPMS sensor is remounted to the wheel, position the wheel/tire on the tire machine so that the sensor is located about 270 degrees from the mounting head before attempting to begin pressing the tire bead onto the rim. This will minimize risk of damage. \
    Jesse Sez: If you're ever in a midget-tossing contest, always go for the happy midget. It is definitely much harder to toss them when they're unhappy

  4. #4

    Re: Tire Pressure Monitoring Systems (can we sticky this please)

    Sticky

  5. #5

    Re: Tire Pressure Monitoring Systems (can we sticky this please)

    A Tire Pressure Monitoring System is generally an electronic system designed to monitor the air pressure inside all the pneumatic tires on automobiles, aeroplane undercarriages, straddle-lift carriers, forklifts and other vehicles.




    _________________
    Home security systems

  6. #6

    Re: Tire Pressure Monitoring Systems (can we sticky this please)

    great info

  7. #7

    Re: Tire Pressure Monitoring Systems (can we sticky this please)

    I have the Orange Electronics retrofit TPMS on my 9:
    Â* Â*http://www.amazon.com/gp/product/B002DYH586

    Great unit.Â* You can see the temps and pressures increase within minutes as you start driving and get some heat in the tires.Â* Â*O0

  8. #8

    Re: Tire Pressure Monitoring Systems (can we sticky this please)

    A great information about tire pressure check valve cap set coming from this thread. Great job guys!

  9. #9

    Re: Tire Pressure Monitoring Systems (can we sticky this please)

    Quote Originally Posted by ixmrgg
    I have the Orange Electronics retrofit TPMS on my 9:
    Â* Â*http://www.amazon.com/gp/product/B002DYH586

    Great unit.Â* You can see the temps and pressures increase within minutes as you start driving and get some heat in the tires.Â* Â*O0

    ^^Thats cool!


    RALLI//////////ART

  10. #10

    Re: Tire Pressure Monitoring Systems (can we sticky this please)

    subscribed O0

  11. #11

    Re: Tire Pressure Monitoring Systems (can we sticky this please)

    I've had mine for a couple years know, and it still works fine.Â*

    Here's some more info:

    Manufacturer site:
    http://www.orangetpmsusa.com/afterma...er-car-tpms-2/

    Another vendor:
    http://www.vulcantire.com/orange_409_sys.htm

    The only issue I have with the system is that the beep it makes on startup gets a little tedious.Â* When I get a chance, I'm gonna try and come up with a way to mute it some.Â* I can give an update if anyone is interested.

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