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2009 Subaru Legacy Limited - TPMS Light

34 messages,  Last post on Feb 12, 2011 at 7:22 PM

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What is this discussion about? Subaru Legacy, Subaru Outback, Sedan, Wagon

Messages Page 2 of 4

#11 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [xwesx] by pilot1226

Feb 17, 2010 (6:25 pm)

Replying to: xwesx (Feb 17, 2010 5:32 pm)
I suppose anything's possible. We live in Northern NJ so it's pothole central up here, and the constant snow accumulation & plowing certainly isn't helping them go away.
 
My wife and I were pretty stunned when we were told it's typical pothole damage to the tire & rim, because neither of us (she is the primary drive, though I do take it from time to time) recalled any "jolting" potholes like they were describing.
 
I'll keep that in mind when I check the tires tomorrow - since rotations follow a standard path, I'll see if it was "behind" the front passenger side that was actually damaged. I'll go dig out my paperwork and find out how many rotations I've done. Pretty sure I've done 2 so far - 7500 and 15000. So, it all depends on where they mounted the replacement.

#12 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [pilot1226] by fibber2

Feb 17, 2010 (6:42 pm)

Replying to: pilot1226 (Feb 17, 2010 6:25 pm)
It's good that we're 'double teaming' this, as Wes brought up an excellent point to look at the other tire on the same side as that might be the current leaker.
 
OEM wheels are way overpriced. I bought respectable looking alloy rims from TireRack for both our Outback and Honda Odyssey with snow tires (I live a 100 or so miles north of you). A set of 4 was cheaper than a single OEM rim for either vehicle.
 
Remember a couple of rules regarding Subaru AWD systems:
1) Rotate front to back - do not cross (I never understood this one, but it's what they say).
2) Tire circumference must be close to the same all around to not put stress on the center differential. See your owners manual for details. They recommend replacing tires in pairs if there is a substantial difference in thread depth.

#13 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [fibber2] by pilot1226

Feb 18, 2010 (7:00 am)

Replying to: fibber2 (Feb 17, 2010 6:42 pm)
I'm almost positive that my tires are not directional and follow a standard rotation pattern. Either way, I've done all my rotations at my Subaru dealer nearby, so if that was done in error, it's their problem.
 
I'm familiar with the circumference issue. It seems like the spare tire is 16" whereas the other tires are 17". I remember reading the owner's manual when we first got the car and it included instructions on disabling the AWD via a fuse.
 
Alright, out to the car now to see the which was replaced.

#14 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [pilot1226] by pilot1226

Feb 18, 2010 (7:38 am)

Replying to: pilot1226 (Feb 18, 2010 7:00 am)
Service Papers in hand and pictures of the tires...
 
12/15/08 - 3750 mi service
04/14/09 - 7500 mi service (Tire Rotation)
04/16/09 - Passenger Rear Tire replaced (sidewall bubble)
07/24/09 - 11250 mi service
11/10/09 - 15000 mi service (Tire Rotation)
 
So, looking at the pictures:
 
Passenger Front: fdh4 nxf4907
Passenger Rear: fdh4 nxf4907*
Driver Rear: fdh4 nxf1908
Driver Front: fdh4 nxf4907
 
So, we can see that the Driver Rear tire is the one that was replaced as this DOT number matches my documentation from the shop where I replaced the tire. Given the 2 rotations, it appears that the replaced tire has followed the typical rotations per the Subaru owner's manual below:
 
[IMG]http://i48.photobucket.com/albums/f203/disregardec/subaru.jpg[/IMG]
 
Whether the dealer actually follows this or not, I don't know. I know that my previous car, a Civic, had a different rotation path even with non-directional tires.
 
So, it seems like between the two rotations, the passenger rear went to the driver front, then the driver rear where it is now.
 
This means that the tire with the persistent TPMS light was on the Driver Rear at the time the other had the sidewall bubble - on the other side of the car. So, to me, this rules out mauling a curb or the same pothole being the culprit. Again, a lot of this "theory" depends on whether or not they were rotated the way the owner's manual said, but so far, all my rotations have been done by the dealer. And, we ruled out that it's definitely not my new tire that's leaking, which is a relief.
 
I didn't see a nail or anything irregular in the treads themselves. Either way I'll have the dealer look at it when I take it in for the 18,750 mi service next week.

#15 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [pilot1226] by xwesx

Feb 18, 2010 (10:42 am)

Replying to: pilot1226 (Feb 18, 2010 7:38 am)
Either way I'll have the dealer look at it when I take it in for the 18,750 mi service next week.
 
Sounds like a good plan at this point.

#16 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [pilot1226] by fibber2

Feb 18, 2010 (8:01 pm)

Replying to: pilot1226 (Feb 18, 2010 7:38 am)
Now there's an interesting fun fact. Subaru has changed it's long standing tire rotation policy and now recommends cross-rotation??? In my previous post, I was advising you to follow what appears to be an outdated set of instructions.
 
From my owners manual:
Tire wear varies from wheel to wheel. To maximize the life of each tire
and ensure that the tires wear uniformly, it is best to rotate the tires every
7,500 miles (12,500 km). Rotating the tires involves switching the front
and rear tires on the right-hand side of the vehicle and similarly switching
the front and rear tires on the left-hand side of the vehicle. (Each tire
must be kept on its original side of the vehicle.)

#17 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [fibber2] by pilot1226

Mar 04, 2010 (5:49 pm)

Replying to: fibber2 (Feb 18, 2010 8:01 pm)
Well, I had the car serviced today. They took the tire off and put it in a tire bath and basically came to the conclusion that there's no air escaping from it. So, I guess that's good news. No nail or any other irregular markings to suggest tire damage.
 
The dealer suggested that if I continue to have the issue that I take the car to a tire shop because they have some more advanced equipment.
 
Shrug.
 
Not sure if I asked this above, but is it possible for the Subaru TPMS system to "vent" when the pressure is too high? Reason I ask is because I'm wondering if the recent heat changes in my neck of the woods could contribute to the light coming on. (From weather in the 50's to the 20's).
 
Otherwise, I'll have to keep an eye on it. The light came on today while driving it to the dealer for service, but before that, it was good for about 2 weeks without filling it.

#18 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [pilot1226] by fibber2

Mar 05, 2010 (5:42 am)

Replying to: pilot1226 (Mar 04, 2010 5:49 pm)
Not that I have ever heard. It is simply a monitor system, and not reactive.
 
I still think there is a leak somewhere. The problem with a tire bath is that it is a 'no-load' test. Your tire might only leak out a small amount of air during certain dynamic operations, such as hitting a bump or pothole, cornering loads that push against the bead, when hot and the internal pressure exceeds a certain threshold, etc.
 
It could be a rim problem, where the tire meets the rim, or the TPMS/valve unit itself.

#19 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [fibber2] by pilot1226

Mar 06, 2010 (9:27 am)

Replying to: fibber2 (Mar 05, 2010 5:42 am)
Okay, that makes sense. So, if I bring it to the shop where I had the one tire replaced (a Yokohama retailer nearby), what kind of test(s) should I be asking for, and what's a reasonable price for it?

#20 of 34 Re: 2009 Subaru Legacy Limited - TPMS Light [pilot1226] by snowbelter

Mar 06, 2010 (10:15 am)

Replying to: pilot1226 (Mar 06, 2010 9:27 am)
I had a slow leak (1 lb/wk) on my 07 and took it to a tire place. They used a water bath and had trouble finding a leak, but finally found a leak around the tiny gasket used to attach the TPMS unit to the rim. They showed me where it was corroded, but not from rust.
 
They told me that the material the gasket was made of was reactive to the alloy wheels which caused corrosion and then a leak. They replaced the gasket with one of a different material. They said there was a Bulletin out on the problem.
 
I don't remember whether the new gasket was silicone or whether silicone was the one that was reactive to the wheels.
 
I later mentioned this to my Subaru dealer, and they were not aware of the problem.
 
We've also had slow leaks around the rim due to corrosion from the salt used on the roads here. I don't think your car is old enough for your leak to be due to this problem.

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