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Tire Pressure Sensor reset and spare tire


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Hi Folks,

 

My 2012 Legacy is showing the fault light for the Tire Pressure Monitor Sensor.  The light blinks for about a minute, and then stays constant.  The owners manual says that this indicates the TMPS itself has a fault, and likely needs a reset.

 

No tires have been change, the pressures in the road tires are fine.  I have not checked the spare yet.

 

Can someone please tell me if the spare is also hooked up to the TMPS, or only the road wheels?  I have no idea what caused this alert to go off or if would happen again after a reset.  Also, if this just needs a reset, what is a fair price for that?

 

 

Thanks in advance,

 

Ratterrier

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If the light is blinking that means there is a problem with one of the sensors, or the receiver control unit. Either one of the sensors has stopped responding, or for some reason the control unit has lost its programming or has some type of electrical fault.

From other Subarus I've seen, the temporary spare does not have a sensor.

 

You can try resetting the system by installing a fuse in the test port in the underhood fuse panel.

Open the top and you'll find a lone empty fuse hole in the back right corner. It is unlabeled. This is called the PDI fuse on newer Subarus. Insert a spare fuse of any rating (also should be in the fuse panel) into the holder and turn the ignition switch to On for a few seconds. You'll hear some clicking and the radiator fans will cycle on and off a few times. Turn the key Off, and remove the fuse. Put it back in its spare holder and reinstall the cover. Take the car for a drive at about 25 mph for 3-5 minutes to for the TPMS system relearn the sensor pressures.

 

If it still blinks it will likely need to go to a dealer for a diagnostic.

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Thanks for the reply Sooberoo.

 

Maybe my description wasn't clear enough.  The light only blinks for about a minute, and then stays on.   The manual says this indicates that the TPMS system itself is faulty, rather than a tire having low pressure.   I'm reading into your message that maybe that is what you understand also...the system itself.   So I will give the fuse idea a try...seems harmless enough.

 

Also, thanks for the info about the spare.

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raterrierdog,

 

The symptoms you describe is exactly what my 2012 (an imported US car) has done in the past. At present, I have winter tires installed on steel subie wheels with no sensors in them, and the TPMS light starts blinking at start up, and after several instances of this, the light stays on solid.

 

When I put the summer mag wheels (with the sensors installed) in the spring, the light doesn`t come on.

 

I have had one tire lose pressure (nail) and after the fix, the light came on solid, even though all four tires were up to the proper pressure. So I tricked the system, pressured all of the tires up by 6 psi over the recommended pressure and drove about 3 miles until the light went off. Once home again, I dropped the pressure back down to the recommended reading, and the TPMS light stayed off.

 

You might have to do the same trick, because I don`t think that your TPMS system is faulty. Been there, done that. Good Luck!

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Update on the TPMS.

 

As Sooberoo suggested, I placed the spare 10A fuse into the PDI (pre-delivery inspection) slot and turned on the power only for maybe 10 - 15 seconds.  I did hear the fans cycling at least twice.  The TPMS fault light continued to blink during the power up.  I wasn't sure if it was supposed to vanish wile I was doing this, but since I heard the fans a couple times I ended my test and removed the fuse.

 

I took the car out for a short ride, but had the same result.  Light blinked for a bit, then stayed on solid.

 

If I did this properly, then I guess I'm going to get that diagnostic from the dealer.

 

Thanks again.

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Only other idea I can suggest is to unhook the battery negative for 15-20 minutes then reconnect.

 

More than likely one of the sensors is not responding. A lot of tire shops now have TPMS scanners that can read and reset the sensors. You might try calling a few and see what they charge to check the sensors. If it's not a sensor issue, it will need to go to a dealer.

Edited by Fairtax4me
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My 2006 sedan is having problems like this.  Any reason not to replace them with regular valve stems and remove the bulb from the instrument cluster?

Some tire shops will refuse service if they know your car has it and/ or is required by law... US Govt mandate after 2008..

 

It's generally not illegal to have a non functional TPMS, but a tire shop would be held responsible to ensure that a TPMS is functioning after they have performed service on that wheel.. Generally speaking, they could note on the work order a TPMS is faulty, but they cannot service a wheel that does not have TPMS that should, because ultimatly any liability would point to them, because they are goverment mandated

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