TPMS crying wolf

[Pee-wee German]

I just went out to the garage with my dial gauge and my digital (I don't own a pen gauge). Yeah, the readings are similar. I'm seriously considering inflating to 50psi just to be safe.

[SmartDigger]

Originally Posted by smartacus

Oh come on, the TPMS light WILL NOT illuminate for too much psi. Smart Center themselves explained to me and I quote :" you can fill it with 80psi and it will still only alert to low pressure."

Why doesn't TPMS alert you that a tire is too full while you are rolling those tires on the highway or too low when you get off the highway and into fresh snow (much less after sitting cold and parked for 8 hours)?

I wasn't in the dark about its operation; (which I can't say about others), I was just wondering if ANYBODY ELSE had a TPMS crying wolf.

What you say is true as long as you reset the dash button. If you pump them up to 80psi and reset the system, then it will think your 80psi in normal. That is until the tire blows.

[Godfather]

Common sense was trampled to death last week....... the guy who did it had on a TPMS shirt............

[fortow]

Originally Posted by smartacus

Oh come on, the TPMS light WILL NOT illuminate for too much psi. ...

Yes they do - they work by alerting to variations in pressure both positive and negative. I don't know what the exact allowable variations are beyond the set pressure for the smart pressure monitors. Pressure variations before warning differs for different systems but it is usually about 20-30%. The high pressure warning might be a greater variance than the low pressure warning though. You will be notified if the pressures do go too high.

One of the reasons for the high pressure warning is because if you set the pressures too low, then after driving the pressure increase will be more than normal since the tires will be generating more heat. If you do get a high pressure warning then check to see if your cold setting is at the recommended pressures. Also, if you set the pressures correctly but over inflate the tires you will also get a warning.

[Pee-wee German]

Originally Posted by fortow

Yes they do - they work by alerting to variations in pressure both positive and negative. I don't know what the exact allowable variations are beyond the set pressure for the smart pressure monitors. Pressure variations before warning differs for different systems but it is usually about 20-30%. The high pressure warning might be a greater variance than the low pressure warning though. You will be notified if the pressures do go too high.

One of the reasons for the high pressure warning is because if you set the pressures too low, then after driving the pressure increase will be more than normal since the tires will be generating more heat. If you do get a high pressure warning then check to see if your cold setting is at the recommended pressures. Also, if you set the pressures correctly but over inflate the tires you will also get a warning.

Oh come on. No they don't... You are confusing our TPMS with an aftermarket product I've been thinking about getting for my motorcycles.

NHTSA mandated alert comes on at a loss of 25% pressure. It has its history in the FORD EXPLORER/ FIRESTONE WILDERNESS AT tires issue from a decade ago.

Our smarts don't have a high psi dummy light only a low psi dummy light. How would that class action lawsuit discovery go if the warning light pictogram is of a low tire and Maybell overfills an overfilled tire even worse causing a catastrophic blowout? In a car that some people would love to ban from the highway... C'mon ; Roger Penske would never have believed in the car.

[fortow]

Originally Posted by smartacus

Oh come on. No they don't...

You may be correct since some systems are designed to provide warnings for only low pressure, and that was the mandate after all. My comments were generalized and not specific to the smart system. I do not know if the smart system actually does warn for high pressure. I will check that out.

[PerryA]

I get TPMS "wolf" when the ambient temperature drops and the car has been sitting. I drive a little while, the tires warm from all the motion/friction, and the pressure warning disappears. I call it the Costanza effect - there's shrinkage in the cold, including tire pressure. If the light doesn't go out after I've driven the car a few miles, I top up the pressure.

[jimvw57]

I run my tires at the factory reccomended pressures and check them frequently, adjust as needed. My only problem was using an inaccurate gauge which got replaced with a digital one. No more problems.

Not sure why you'd want to run tires at a higher pressure than the factory reccomended pressures unless the tires are made for it, or a special application.

I thought I saw some TPMS sensors at the tire shop that were set for different pressure ranges. I could be wrong.

[Pee-wee German]

Now my TPMS keeps going off every 5 minutes. not blinking , just solid. My tires are at 40psi.
And now my speedometer shows 75MPH while my scangauge reads 90MPH.

[jimvw57]

Sounds like it is time to contact the dealer for a computer check-up. At least give them a call with the symtoms. At 75 MPH you should be passing some cars, at 90MPH you should be passing all the cars. Could be as simpe as a bad ground or as serious as a bad computer. Only a dealer could say for sure.