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Discussion Starter #1
Okay, I must admit I am a little envious of the tire pressure monitoring system on my wife's mini van. I am wondering (if I could find one) how hard it would be to install a factory unit from an early 2000s model car into my 2002 300M. Any help, ideas, or suggestions? (I really do not want an aftermarket unit.)
Thanks, Mark
 

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Radioactive
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5,347 Posts
Mark,

First, give your head a shake. :)

These systems are only there to meet a regulatory requirement.

They provide more nusense alarms than protection, and even the owners manual tells you not to trust them... it recommneds checking the pressures regularly with a gauge.

They add to the cost of replacing wheels, and introduce several additional failure modes.
 

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Super Moderator
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You would probably need to find an LH donor car with this option. I believe that the SKIM module (which you should already have) is used as the wireless control module to pick up the TPM sensor signal. You may need this WCM from the donor in order to facilitate the TPM feature. It might help to find someone who has done this before, even if it is worth doing or not:

Some versions of this vehicle are equipped with a Tire Pressure Monitoring (TPM) system. It monitors air pressure in all five tires (includes full-size spare).
There is a sensor (transmitter) in each of the vehicle's five wheels. The system alerts the driver when tire pressure falls outside predetermined thresholds (pressure too low or too high). A message is then displayed on the Electronic Vehicle Information Center (EVIC) located in the overhead console. Tire air pressures in the four road wheels are displayed on the EVIC when chosen. Pressure in the spare tire, although monitored, is not displayed on the EVIC.
The Tire Pressure Monitoring (TPM) system uses wireless technology to monitor tire air pressure levels. Sensors, mounted to each road wheel as part of the valve stem, transmit tire pressure readings to a receiver located in the overhead console. These transmissions occur once every minute at speeds over 20 mph (32 km/h). The tire pressure status is shown on the Electronic Vehicle Information Center (EVIC) display upon demand. The Tire Pressure Monitoring system remains active even if it is not displayed in the EVIC.

If any road tire pressure has exceeded the low or high pressure threshold (refer to chart below), the TPM system will display a message on the EVIC and sound a chime. It will then go into the tire pressure display screen and flash the pressure value of the tire that is low or high. This will be displayed for the rest of the ignition cycle, or until either the C/T, MENU, STEP or RESET button is pressed.

If a road tire is replaced by the spare, the TPM system will detect the swap automatically (after the ignition has been cycled) and display "SPARE SWAP DETECTED" along with a chime (This could take up to 10 minutes with the vehicle speed above 20 mph (32 km/h).

NOTE: TPM thresholds have been established for the original tire size equipped on the vehicle.


CAUTION: The use of tire sealants is strictly prohibited for vehicles equipped with the Tire Pressure Monitoring system. Tire sealants can clog tire pressure sensors.


WARNING: DO NOT USE THE EVIC DISPLAY TO MONITOR AIR PRESSURE CHANGES WHILE ADJUSTING AIR PRESSURE IN THE TIRES. THE TPM SYSTEM CANNOT BE EXPECTED TO FUNCTION AS A REAL TIME TIRE PRESSURE GAUGE. THERE CAN BE A DELAY BETWEEN THE INSTANT THE AIR PRESSURE IS ADJUSTED IN A TIRE AND WHEN THE SYSTEM UPDATES THE DISPLAY.
 

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KOG
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6,999 Posts
Actually those systems can work well. And there are aftermarket ones which you could use. They are on all new cars because they are now required by law and they are rather pricey little devils overall. Be aware that there are two major types: those which monitor wheel speed using ABS sensors and trigger an alarm if one wheel starts running faster than the other, and those which have sensors actually measuring pressure in each tire. The after market ones will be only pressure sensors which are more expensive, and more accurate in general than the speed sensors.

One major drawback: in the case of our 09 T&C which specifies 35 psi in all tires it is not possible to set the rear tires at say 30psi for improved ride when running with no load as that triggers the alarm. That's a real nuisance as we run empty most of the time. Aftermarket systems allow you to set the alarm pressure level for each wheel individually.
 
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