tire pressure monitoring system on 05 expedition

Driving home from Abilene, Texas to Sugar Land, Texas (about 350 miles) yesterday, my tire pressure monitoring system came on twice for a couple of miles with a system failure message in my 2005 EB Expedition. I stopped the first time and visually inspected the tires. Hitting the reset button cleared the message each time.

I have about 26K on this truck with no problems whatsover. I have a semi new set of Michelins on it with about 8K miles (the orginal Continentals were crap).

Could it be something on highway 36 was messing with the RFID system this uses (I think) ? Or, is my tire pressure monitoring system getting ready to fail ?

Thanks, Lynn

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I assume you verified that the tires were properly inflated? You need to check the prssure when the tires are cold at outside ambient temperatures. They need to be properly inflated within 3 psi.

Ford cautions that the valve stems can be damaged by improper treatment. There is also a procedure for re-training the tire sensors, but it requires a special tool (really just a big donut magnet).

What was the exact message? I believe the possible message are:

"TIRE PRESSURE MONITOR FAULT". "TIRE PRESSURE SENSOR FAULT" "LOW TIRE PRESSURE"

Ford provides the following warning:

"Ambient Temperature Change and Tire Pressure

"If tire pressure is adjusted/set indoors, additional care is needed in the winter months to achieve the correct inflation pressure. Since the tire pressure will drop with temperature, the tires need to be inflated above the specifications given on the vehicle certification (VC) label while indoors during winter months, so the tire pressure is at the pressure listed on the VC label when parked outdoors.

"As the ambient temperature decreases by 12C (10F), tire pressure decreases 7 kPa (1 psi). Adjust the tire pressure by 7 kPa (1 psi) for each 12C (10F) ambient temperature drop as necessary to keep the tire at the specified vehicle placard pressure. For additional information on tire pressure adjustment, refer to the following table."

I would wonder if the sensors might have been damaged when the tires were changed. Here is a little information on the sensors:

"Each tire pressure sensor transmits a specific radio frequency to the TPMS module once every minute when the vehicle ignition is on. The tire pressure sensor valve stem serves as an antenna which sends the radio signal to the TPMS module. The tire pressure sensor is battery powered. "

Do all your valve stems look OK?

Which Michelin Tires did you purchase?

Did the tire dealer understand the tire pressure monitoring system requirements? Mounting new tires might require the sensors to be reset. Did they do that?

Before you purchased your repalcemet tires did you read the following information in your owner's guide?

"The installation of replacement tires with steel cord body plies in the tire sidewall may cause malfunction of the Tire Pressure Monitoring System (TPMS), and is not recommended (cord material information is molded on the tire sidewall). Additionally, if your vehicle was originally equipped with run-flat tires, replacing them with tires that are not identical to those originally fitted may cause malfunction of the TPMS, and is not recommended. Run-flat tires should not be used to replace regular tires. Always check your TPMS indicator immediately after replacing one or more tires on your vehicle. If the TPMS indicator is on, your TPMS is malfunctioning. Your replacement tire might be incompatible with your TPMS system, or some component of the TPMS system may be damaged."

....

"Important: Remember to replace the wheel air valves when the road tires are replaced on your vehicle."

If your vehicle is still under warranty, I suggest you take it to the dealer.

I recommend you join the Expedition Owners Mailing List See: http://mail.xpog.com/mailman/listinfo/expedition

Ed

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They looked OK. Sidewalls were stiff and not buldging.

TIME PRESSURE MONITOR FAULT, I believe. The word FAULT was definitely in there.

It has been 8,000 miles since I replaced the tires. I have been to California and back (3500 miles) and this is my 2nd trip to Abilene (750 mile round trip).

I am surprised it is not 60 times per minute. Hmmm, battery powered sounds fraught with failure since that pressure sensor is in a very harsh environment.

yes.

Michelin X tires from Sams Club.

Nope and nope.

Nope.

Dont know.

Thanks, Lynn

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You need to actually check the pressure with a gauge. Looks can be deceiving, especially with radial tires. Be sure to inflate them to the correct pressure listed on the vehicles information placard.

Sound like you should take it to the dealer. The monitor system stores fault codes that the dealer can retrieve.

The monitor is safe inside a closed environement. It probably gets a lot of shock, but that won't hurt a battery. If you want to directly monitor tire pressure this is about the only way to do it. There are other systems that determine that a tire is loosing pressure by using the ABS wheel speed sensors, but they are less accurate and less responsive and are upset it the tires aren't matched or when you rotate the tires.

I don't think these shoul dbe a problem ( are they P series tires?).

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I know but I could reset the system OK. Even restarted the engine and did not get the message again.

I will if it hits again.

Yes, sounds like a good system.

P265R75-17, I believe.

Thanks, Lynn

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TPMS operates on different frequencies according to the vendor; some are 2.4GHz ISM, some are 315 or 433MHz. All of these frequencies are unlicensed(*) and subject to interference. It is possible - but not real likely - that you were experiencing interference from a 2.4GHz RFID system - these are sometimes used for tracking trucks and shipping containers.

(*) in the technical sense of the term.

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Maybe just pull the fuse and be done with the ridicuous monitoring system. You can check manually with no stupid codes

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