Tire pressure monitor failure or dealer cash grab?

Rewted · 05-25-2010, 09:21 AM

I recently took my 335i in for maintenance and the dealer discovered one of the run flat tires had a nail in the sidewall. They said the tire was completely flat, yet the tire pressure monitor indicated no such degradation. How is this possible, is the sensor malfunctioning or did I waste money on a new tire?

MusclezMarinara · 05-25-2010, 10:24 AM

should of had them do a pressure test and show you the failure

Rewted · 05-25-2010, 03:12 PM

Quote:

Originally Posted by Takashi

CAD BMW (If I am correct) dont' have a sensor inside the tire. Such system relies on rotation speed of each tire to determine if one is flat or not.

Nevertheless, one should check tie pressure every week (and before dealer service) to minimize surprises.

So how would one know if they had a flat or not? As previously mentioned, they said the tire had NO air in it. But I was driving as if things were normal.

VTECaddict · 05-25-2010, 03:21 PM

The runflats make it harder for the FTM to show a flat immediately since they keep their shape even with no air in it. The only way to know a RFT is low on air is to check it, because visually it will always look inflated.

TPMS actually monitors the air pressure instead of just rotation speed, so it would have triggered a warning.

e90fanatic · 05-25-2010, 03:24 PM

from my experience 2006 cars uses rotation to determine tire pressure but 2007 onwards use TPMS sensors in tires.

smallseafishie · 05-25-2010, 03:48 PM

Quote:

Originally Posted by e90fanatic

from my experience 2006 cars uses rotation to determine tire pressure but 2007 onwards use TPMS sensors in tires.

Actually 03/07 and onwards have them.

dcat151 · 05-25-2010, 03:51 PM

Yea, the earlier system that uses rotation of the tire to determine if one is flat is the FTM system.

VTECaddict · 05-25-2010, 04:14 PM

Quote:

Originally Posted by smallseafishie

Actually 03/07 and onwards have them.

For US cars, yes. But OP is from Canada and the BMW Canada site doesn't really go into detail as to which one they use. Perhaps our Canadian members can chime in?

John 070 · 05-25-2010, 05:00 PM

Please don't tell me that when you asked to see the tire, they couldn't find it. My dad used to fall for that all the time, but one day, he got really mad and I was really proud. They installed a used alternator and charged him for a new one. It had the year written on it with a yellow grease pencil. I never seen my dad bully anyone before but he nearly killed that service mgr., at least with his words (he's good with them).

Rewted · 06-02-2010, 10:58 AM

Well the car is a 2008, so based upon what has been said here, TPMS sensors should be in tires.
Would this not trigger the tire pressure sensor indicator on the dash console to lite up?

If this is not the case, how the hell would you know if a tire was flat (aside from a physical check). I can't see BMW allowing that.

Wires · 06-02-2010, 03:24 PM

Quote:

Originally Posted by tyrewt

So how would one know if they had a flat or not? As previously mentioned, they said the tire had NO air in it. But I was driving as if things were normal.

Could have had the TPM reset with a flat tire...

It's pretty much impossible to notice the tire being flat just from driving.

05-25-2010, 09:21 AM	#1
Rewted Captain 314 Rep 909 Posts Drives: M3 Join Date: Mar 2007 Location: Canada iTrader: (0)	Tire pressure monitor failure or dealer cash grab? I recently took my 335i in for maintenance and the dealer discovered one of the run flat tires had a nail in the sidewall. They said the tire was completely flat, yet the tire pressure monitor indicated no such degradation. How is this possible, is the sensor malfunctioning or did I waste money on a new tire?
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05-25-2010, 10:24 AM	#2
MusclezMarinara Banned 262 Rep 5,018 Posts Drives: VALNCYA Join Date: Jan 2009 Location: Jersey iTrader: (23) Garage List 2011 BMW 1M [9.22] 2009 335i Sedan xdrive [9.34]	should of had them do a pressure test and show you the failure
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05-25-2010, 03:21 PM	#4
VTECaddict Where'd my VTEC go? 481 Rep 6,067 Posts Drives: 06 330i 6MT Join Date: Mar 2009 Location: Seattle, WA iTrader: (4)	The runflats make it harder for the FTM to show a flat immediately since they keep their shape even with no air in it. The only way to know a RFT is low on air is to check it, because visually it will always look inflated. TPMS actually monitors the air pressure instead of just rotation speed, so it would have triggered a warning. __________________ AW/Terra \| ZSP \| ZPP \| ZCW \| iDrive \| CA Mods: BC BR coilovers \| Blacklines \| M-tech rear \| dual exhaust \| M3 steering wheel \| BMW SSK \| ZHP shift knob \| High-kick CF spoiler \| NBT Retrofit M3 front control arms \| M3 rear guide rods \| Manzo rear toe and camber links \| Monroe rear shock mounts \| Varrstoen ES1 19x9.5+20 Front, 19x11+25 rear
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05-25-2010, 03:24 PM	#5
e90fanatic Absolute0 168 Rep 5,078 Posts Drives: Has a Roundel Join Date: Apr 2005 Location: TO/HK/NJ iTrader: (6)	from my experience 2006 cars uses rotation to determine tire pressure but 2007 onwards use TPMS sensors in tires.
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05-25-2010, 03:51 PM	#7
dcat151 Lieutenant 21 Rep 582 Posts Drives: 2006 330i 6MT ZSP/ZPP/ZCW Join Date: Nov 2009 Location: Gainesville, GA iTrader: (1)	Yea, the earlier system that uses rotation of the tire to determine if one is flat is the FTM system.
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05-25-2010, 05:00 PM	#9
John 070 Lieutenant General 1706 Rep 14,829 Posts Drives: 335i cpe Join Date: Oct 2006 Location: ZSP/ZPP/ZCW iTrader: (0)	Please don't tell me that when you asked to see the tire, they couldn't find it. My dad used to fall for that all the time, but one day, he got really mad and I was really proud. They installed a used alternator and charged him for a new one. It had the year written on it with a yellow grease pencil. I never seen my dad bully anyone before but he nearly killed that service mgr., at least with his words (he's good with them).
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06-02-2010, 10:58 AM	#10
Rewted Captain 314 Rep 909 Posts Drives: M3 Join Date: Mar 2007 Location: Canada iTrader: (0)	Well the car is a 2008, so based upon what has been said here, TPMS sensors should be in tires. Would this not trigger the tire pressure sensor indicator on the dash console to lite up? If this is not the case, how the hell would you know if a tire was flat (aside from a physical check). I can't see BMW allowing that.
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