Lot's of conflicting reports on the whole issue with replacement wheels without the wheel sensors. Have a question based on a theory I have.

Since the sensors don't turn on till the wheels hit a certain speed, is it possible that they do not transmit a low pressure signal unless they're turned on? For example, if you're not moving, and the tire goes flat, no warning light/buzzer. Only get the warning when you're moving over the minimum turn-on speed.

If this is true, wouldn't a new set of wheels not trigger the warning light since the system would just think the units were not on?

Or is the reverse true, when the wheels are spinning and they get no signal, you get the warning, kind of a fail safe so you know if the sensors were not working, dead battery, etc. My guess is that would be a huge pain in the butt, although it would make more money for the dealerships who would have cars in for this issue, and would have to take the wheels apart to find out which unit was bad?

Either way, seems like a bad design. I was wondering why the wheels had the big strip of wheel balance weights. I'm guessing this will cause enough problems for Mazda that they won't try the "there's no spare tire, but we have this warning system" option on cars. The first time I heard that at a dealer, I didn't think wow, that's cool, I thought, that's a really bad idea.

 

Hi SteveK,
This is based on what others have said and this doc that describes the system:
http://www.finishlineperformance.com...02-002-03.html

1) The sensors are battery operated (10 year life) and have a switch that turns on when the tires are spinning at a certain RPM (12 mph).

2) If you have a flat when the car is off, after you start the car, you won't get any indication on the dashboard until you've driven at least 3 minutes over 12 mph. I hope the car's handling would tip us off that's something is wrong if a tire was flat.

3) Others have posted that when they mounted their winter wheels with no sensors, they got the flashing TPMS light. I imagine the TPMS looks for a signal from the wheel units after 15?? minutes of driving, and if it does not get the signals - system alert - flashing light - to let you know something's wrong!

4) The big strip of wheel weights is to counterbalance the wheel units (sensors).

Based on the above, I decided to by wheels with sensors. I think that flashing light, especially at night, would drive me nuts .

Some people have said they are going to tape over the light. Watch out for glue residue.

Hope that answers you questions.

regards,
rx8cited

 

fwiw, on the first few cold mornings of this season, I got the TPMS warning light when I first started my car in the morning before work, before I'd driven it anywhere. After I drove to the service station, and pumped up my tires to proper pressure, when I started the car again, the light was off... before I'd driven away from the station. So, I don't think the monitors necessarily wait until you've gone 3 mins over 12mph...

I think you're thinking of the registration process for the TPMS after changing a tire to one with a new sensor; this is from the owners manual:

"When changing tires yourself
If you or someone else changes tires, you
or someone else can also undertake the
steps for the TPMS to complete the ID
signal code registration.
1. After tires have been changed, turn the
ignition switch to the ON position, then
turn it back to the ACC or LOCK
position.
2. Wait for about 15 minutes.
3. After about 15 minutes, drive the
vehicle at a speed of at least 20 km/h
(12 mph) for several minutes and the
tire pressure sensor ID signal code will
be registered automatically."

 

Mazda didn't put the TPMS system on because they thought it was a great idea - they put it on because the US government requires it. Where it's NOT a government requirement, like in Canada, Mazda didn't bother with the TPMS.

Regards,
Gordon

 

hi jdaled,

Interesting........ thanks for sharing your observations.

The service bulletin says the wheel units have a switch that is turned on only if the car is going over 12mph ...... so I wonder how your TPMS warning light came on if the car was not moving?

There's also a NOTE that says the TPMS light cannot be turned on or off by the system until the vehicle is driven over 12 mph. You're experiencing that the light can turn on / off without the car even moving - somethings not adding up here?


regards,
rx8cited