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Installed rims with no PSI transmitters. Why no "Low PSI" indication?

Mounted and balanced aggressive snow tires on four donated rims which have no tire pressure transmitters.

Why no expected low pressure indication in the instrument panel?

How do these transmitters work?

Batteries which will eventually need replacing?

Thank you,


Perhaps your cars data has been captured and now the reciever in the car is getting its data from the National Tire Pressure Monitoring Spoffing Center. What will happen is a "low tire"light will come on and those people that have been following you will “snatch” you when you pull over and check your tire. :0) NOTE EMOTION SYMBOL.

I played around a bit because not having a indicator inside the car when you do not have a complete system should be one of the possible results that you should expect. You feel that the absence of a signal should set a “low tire” code BUT perhaps the absence of a signal puts the system too sleep.

Since you know your system is inop,carry a gague, when your restore the system with all required components and it still does not work them it will be a good use of time to find out why.

2008 Ford Expedition

We inspect the tires daily and after emergency runs and check pressure frequently.

If anyone snatches me, they’d throw me back. That’s also why I need not worry about anal probes from space aliens.

Do the tire pressure transmitters start sending a signal only when the pressure has descended below a certain pressure? Otherwise, I’d expect the transmitter batteries to drain.

I hope you’re aware that the snow tires probably have a significantly lower speed rating than the tires you replaced.

No more 100 mph until spring returns.

Someone at the Ford dealership might be able to explain the lack of a warning light.

265/70R 17 Nokian Nordman SUV 1
115T = 118 mph.
No studs. Someone said studs could fly out over 80 mph.
Max pressure: 47 psi

Like Oldschool guessed, lack of a signal is what the system WANTS. That’s what makes it happy. A signal means trouble…This set-up also provides maximum battery life…The transmitters are dormant until pressure drops to some critical level…

When you are having a slow day at the firehouse, you could take one of the stock tire / wheels and deflate it and bring it near the vehicle. I bet the low tire light comes on…What fun!!

That’s what I was hoping/expecting.
So I’ll be sure to keep the tires on the 18-inch wheels up to pressure.
Can the batteries be replaced?

This is unrelated to a fire department.
But I’m so cheap that I would not want to use ANY battery life of a transmitter.

I suspect that you will get the TPS malfunction warning light in a few days.

Why should it wait!
If such a problem, I’d expect to get an immediate indication.
Otherwise, is it waiting too long, until tire destruction, for a warning?
I’ll post what happens.

No answers yet. 2 techs here don’t know yet and I posted a messege nationwide to other Ford dealers. I only began asking at 5:15 so more in the a.m.

The sensors are battery operated and it baffles my butt as to why they’re not replaceable.
They’re soldered in and covered with a rubbery filler yet they’re just a #2450 3v wafer. Seems wasteful to me too.

The only theory so far, that still defies logic, is that maybe becase you park near them each day the signal is renewed ? It shouldn’t be, but maybe ?

Does the warning lamp illuminate ( is the bulb good ) during self check as you turn the ignition on each time ?
Do the OE rims even have sensors in them ?

Probably because the cost to remove the tire, open the sensor and replace the battery would cost as much, if not more, than to just replace the sensor itself.

Speaking of tires; I agree with not getting studded tires for your application. Unless you live on a road that requires ice travel daily, the difference between studded tires and the newer un-studded for ice traction is not that great.
Loosing a stud while driving at higher speeds may be more of an installation problem. IMO, studded tires handle poorly on dry pavement making high speed driving more of a problem This makes your choice of tires a wise one… but for a different reason.

Just more gimmicks the second and third owners will ignore or discard… correct.
At exactly 30.0 miles (I reset trip odometer when I mounted the sensorless wheels)
some beeps and blinking orange tire crossection icon.

Then light illuminated steadily.
When igniti.ON: Odometereadout: [Tire pressure sensor fault]