SW17LS

Having a weird issue. My spare is showing as low pressure, tripping the TPMS warning, yet the pressure is the same as the other 4 tires which don't register a fault.

Ive tried resetting the TPMS several times and it always comes back up as the spare being low, yet the pressure is the same.

Any thougghts?

droclex

TPMS sensor could be on its way out; it happens. I would swing by a Discount Tire, they can probably replace it for free or a very modest fee. Dealer might overcharge as usual, unless you can convince your SA to cover it gratis. Either way, please let us know how it goes. Good luck!

Doublebase

That is strange, I'd try adding more air into the spare and seeing if that helps. Keep in mind that the pressure in the other tires might rise once they start rolling and expand with heat, meanwhile the spare just sits comfortably in the trunk and won't expand. It may be something as simple as just perhaps over inflating the spare a bit, but most likely it's the sensor itself that's the problem...but these sensors should last seven years, and yours is only a couple years old. Still stranger things have happened.

Rhambler

What pressure is it saying and how are you verifying it? It could really be low and your gauge is bad? Is it really cold where you're at?

like Double mentioned, try filling it until you reach the threshold, which I'm not sure what it is, 29 PSI?

Or maybe the battery is prematurely dying in the sensor.

comotiger

Hi Steve, something stumped you??? That's unbelievable

As DB said, the spare just sits there, maybe the pressure is very near the threshold for tripping the sensor, but the display is not accurate enough to show it. I had this problem a few weeks ago. I inflated the spare to 2-3 psi more than the other tires, and the problem went away. Hopefully, this will solve your problem too. Good luck!

jmcraney

The LS460 TPMS has 5 independently-settable warning thresholds, one for each wheel, including the spare, and they can be set over a wide range. What do you have your warning thresholds set to?

Wheel localization only occurs during benchmarking. Have you rotated your wheels or brought your spare into use since you last benchmarked your TPMS? Not conforming to this can cause the tire pressure display to misrepresent the actual positions.

It is possible to mal-benchmark the TPMS in such a way that it requires special measures to get out of as the system cannot be benchmarked while it is in the Alarm state.

SW17LS

Thanks for the input guys, appreciate it. Yes even I can be stumped!

It started one day when my car was sitting outside And it was very cold. All 5 tires were down to like 24 and it threw codes on all 5. Slowly as it got warmer (the LS is almost always garaged) the tires came back to what I run them at, 30. The spare is at 30 like all the others and it registers as low even though the others don't. I've reset the TPMS multiple times to reset the set point and it makes no difference.

Haven't rotated them or anything or used the spare.

I'd try adding air to the tire but my trunk is full of Christmas presents so I can't easily get to the spare...

If it is a sensor it should be covered under warranty...I'd love to avoid taking it in...and emptying my trunk...

Chuckinnj

I can't believe this thread appeared!!....... I had the exact problem on Monday morning with a low tire pressure warning light.
Here is what I did: Checked all tires and one was low (28 psi) and filled them all to 33 psi with the exception of the spare because I wanted to see where the spare appeared on the "tire psi list" and I drove the car to the store to see how everything was acting......... Tire warning light came back on so I checked the spare and it was low (27psi) so I inflated it to 35 psi and drove it again for about 20 miles and the warning light stayed on.
Insaid to myself: NOW what's the problem??...... So I GUESSED that there may be a problem with the spare tire TPMS so I bled it down to 25 psi and aired it up to 40 psi THEN down to 35 psi and it solved my problem. Tire warning light is off and I am happy!

CRowe14

When I had this issue last Spring, it ended up being that the battery in the TPMS was going dead and I had to replace it.
I think Discount Tire or Tire Barn in my area took care of it for around $50-$60.
I know I could have gotten one off of Amazon cheaper, but if your anything like me, it bothers me to no end to have unnecessary lights on the dash.
Also, get those gifts outta the trunk! Christmas is in 3 days!!

sktn77a

iTrader: (2)

Yeah, on a 2015 LS, I'd just take it in to the dealer after Christmas and get the sensor replaced on their dime!

roadfrog

I'd bet battery weak on the sensor. Mine was doing the same thing. As sson as I put my winter tires on, the problem went away. The local tire shop took a reading on the sensors, and one of them was taking longer than the others to "shake hands" with the scanner. Come Spring, I'll be replacing that one sensor (about 60 bucks).

SW17LS

That's interesting because it reads that sensor last, all of them register but that one takes like a minute before it comes up. I bet it is the battery.

Picture attached of all reading the same and that one being a fault.

sessayan

The easy answer for me is , just take the spare out of the car! Who needs a spare tire anymore ??

1WILLY1

iTrader: (9)

sorry to highjack the thread, I think the battery on my sensors is acting up as well

It was telling me to go to dealer to have them serviced, I added air to tires and it fixed the problem, then after a day or two the warning was back

Where is the cheapest place to get a new set of 4 sensors?

Thanks in advance

roadfrog

SW15LS: Yep....exact same symptoms as me. When the local tire shop attempted to get readings, one of the sensors took a long time to respond, indicating a weak battery in the sensor.

1WILLY1: Cheapest place will be your local tire shop. Check around at your local shops. BigO Tire here was cheapest for me. They warranty mine for two years, Mine are just over that, so I'll have to pay for replacement. I paid about 250 dollars for all four installed (tires re-mounted, balance, etc.)