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Discussion Starter · #1 ·
So I leave for Montreal from NYC this morning. About less than 50miles into the trip, I get a flat tire warning. I was able to pull over to the shoulder to reset the tire monitor but I couldn't check the pressure. I had to drive about 10miles until there was a rest area. During that 10miles the FTM didn't go off again. So I check the pressure and all 4 tires were above 35psi but it wasn't set to the correct psi for each tire. I just had my driver side rear tire replaced about 2 weeks ago. I know the tech checked all 4 tire pressure. I guess he didn't fill it up correctly. I'm not even sure if he reset the FTM after they replaced the tire and added more air to each tire.

So I adjusted all 4 tire pressure to the correct psi and reseted the FTM. Than I drove about over 400miles. The FTM alarm didn't go off again.

So why did my FTM go off? Dealer didn't reset the FTM? But I did drive a few times after the tire change. Why go off now? I did leave my car parked in the underground garage for about over a week. It's a little cool there. And the tires do get flatspot. I left early in the morning when the weather was still cool than maybe the tires heated up and caused the FTM to go off?

So if I was able to drive an additional 400 miles without the FTM going off, does that mean that the tires are fine?

Well I'm in Montreal now.
 

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I would guess your tires are fine since no warnings over the past few hundred miles. I don't know if BMW's TPMS is based on actual pressure or rpm changes, but it does need to be reset after any tire work or inflation. When your tire was replaced earlier I'm guessing the monitor wasn't reset, so that's probably all it was. If it was borderline, it may have changed after you started driving just enough to trigger the alarm.

You should keep an inflation gauge in your car at all times in case you need to check tire pressure. Don't rely solely on the monitor.
 

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Pretty sure it is RPM changes. Not sure why it would have to be reset if it was the same tire installed.
 

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Had a problem with one tire/wheel on my '04 530. One tire would lose pressure occasionally. The FTM would indicate that correctly. The tire could be refilled and would hold pressure for a variable amount of time. It would never go flat and sometimes not even noticeably low , just lose enough pressure to set off the FTM. It seemed to always happen while on the road and never while garaged. We've been out of town for nearly a month and the pressure held but the next time we drove the FTM alerted us. We had the tire and wheel inspected several times and remounted. Finally after over two years a barely visible hairline crack was found in the wheel. Apparently the wheel had to be at a certain temperature for the crack to open enough for air to leak. Although technically not covered by warranty due to possible road hazard damage, BMW did cover half the cost of a new wheel.
 

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Anytime pressures are changed in any tire you MUST reset the TPWS to avoid erroneous tire pressure warnings. Most tire shops and some BMW service centers either don't know this or neglect to do it, hence the erroneous warning. Anytime you check or air up your tires, you must reset the system to avoid the error messages.
 

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So I leave for Montreal from NYC this morning. About less than 50miles into the trip, I get a flat tire warning. I was able to pull over to the shoulder to reset the tire monitor but I couldn't check the pressure. I had to drive about 10miles until there was a rest area. During that 10miles the FTM didn't go off again. So I check the pressure and all 4 tires were above 35psi but it wasn't set to the correct psi for each tire.....

So I adjusted all 4 tire pressure to the correct psi and reseted the FTM. Than I drove about over 400miles. The FTM alarm didn't go off again.....
It is not a good idea to adjust tires to their correct psi after you have been driving for a while as they have heated up and the pressures will be higher. The recommended pressures are for "cold" tires.
 

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Discussion Starter · #7 ·
I did wait for about 15min before I check the psi and adjusted the pressure. I couldn't wait that long.

I thought that the dealer checked the tire pressure already so it should be good. Was I wrong. Next time I will double check it after a visit to the dealer.

If it was the wheel that is losing air, wouldn't it lose air again after 100 miles at 70mph? Especially after over 400miles.
 
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