TPS and bad MPG

[07tundra@10k]

I had an interesting conversation yesterday. The mechanic at my indy shop said he discovered where a tire pressure sensor tells the computer to throw a warning light but will also reduce the power to protect the truck while the pressure is low?? This will lower performance and kill your fuel mileage even more than just the low tire. AND he said he found a Toyota and also a Titan with a TPS in the spare tire and while it was flat the truck had no horsepower!!
Anyone ever heard of this????? I mean it sounds like something possible

[tundratom]

Toyota does not put a TPS sensor on the spare tire. I've had my TPS light come on while towing my trailer. There was no reduced power.

[07tundra@10k]

I know my 07 Limited does not have one in the spare..I checked and it only has a rubber valve stem...
It was an interesting concept though..
NOw if I could just make the VSC stop beeping and blinking permanently I would be a happy camper!!

[blackdemon]

haven't checked my spare as of yet, but I did notice a small power loss when I had a flat tire driving on the 10 a few months back. Not sure if it was the engine, or me noticing my front end leaning to one side, and still having to drive 15 - 20 more miles to make it home. Didn't want to get towed out, or make a wheel change on the notorious 10.

[sxd45]

I noticed when my gas light is on the truck seems to lose a little power, even when I go to fill up it still has 6 gallons in it!

[Skyhammer]

Originally Posted by 07tundra@10k

I had an interesting conversation yesterday. The mechanic at my indy shop said he discovered where a tire pressure sensor tells the computer to throw a warning light but will also reduce the power to protect the truck while the pressure is low?? This will lower performance and kill your fuel mileage even more than just the low tire. AND he said he found a Toyota and also a Titan with a TPS in the spare tire and while it was flat the truck had no horsepower!!
Anyone ever heard of this????? I mean it sounds like something possible

I seriously doubt that having the TPS on will reduce your power. If that were the case the many hundreds if not 1000's of people that have taken eliminated their sensors when they put on new wheels that don't take sensors would have surely have spoken up.
Also, if you put your spare on that doesn't have a sensor, which leaves your TPS gauge on would leave you with reduced power, which is a safety hazard. I also know of some people that do a 5 tire rotation and the spare doesn't have the sensor and they report no problems.
I also have owned two Titans and have driven many miles with the spare with no sensor and had no loss of power.
Last, there is no mention of this in the owners manual or the shop manual.

[catbrown357]

It's a bunch of B.S. I had my spare on for five days just last week, and still waxed a Hemi.

[07tundra@10k]

I dont think everyone is understanding what I said..
IF the spare had a TPS...AND if the tire was flat...the computer would shut down the HP to keep the truck safe. I did not say that just because the spare was on the it wouldnt have HP...

[TampaTundra]

Spare tires in toyotas have a TPS sensor if it is a full size spare and the other 4 have TPS sensors. Same situation with my moms lexus gx470.

Ok 1) My first car, 2005 4runner, had the TPS system. Had several flats as well as a few slow slow leaks all over the 4 year lease. When I would get a flat the light would come on, same in my moms lexus, I would change it out for the spare but the light was still on. At the tire repair shop one time the guy showed me where there is a switch that essentially resets all the sensors. So when I had the repaired tire under the car in the spare tire space and hit the button it would detect the 4 tires that were on the vehicle and ignore the spare, thus turning off the light. 2) never have I ever had either my 4runner or my moms lexus lose any pinch of power, even when I was driving and the moments after I got a flat. One time I was just lazy and had a flat tire just sitting in the back of my 4runner for around 1-2 months before taking it in to get plugged. I never over that or any period of time had any loss of power or decreased fuel mileage.

That is a pretty ignorant/plain dumb "mechanic".

[Toxarch]

Originally Posted by TampaTundra

Spare tires in toyotas have a TPS sensor if it is a full size spare and the other 4 have TPS sensors.

No they don't.

[TampaTundra]

Originally Posted by Toxarch

No they don't.

Yea guess they dont. that explains why the spare that was on my 4runner had a 5th sensor in it, aswell as my moms lexus......and when taking delivery on my truck and going over all the technical details and all of the truck I was told that my spare also has a 5th sensor in it as well, the guy helping me was the salesman we bought it from who knew just about everything relating to the new tundras and even bought his wife one and got one for himself after his current lease was up. And to double check himself on everything there was one of the mechanics there for all the mechanical specs.

Also that explains why there is a button under the steering wheel with the symbol for a low/flat tire. And pressing this button does the sensor reset and picks up then the sensor in the spare that you put on.

[Toxarch]

That's nice. But the 4Runner is not a Tundra. And the Lexus is not a Tundra. The Tundra spare does not have a TMPS in it.

The sensors have serial codes. The codes have to be programmed into the computer. Pushing the reset button just recalibrates the computer for the current air pressure in the tires. It does not "pick up" the sensor in the spare, especially since there isn't one. The computer reads all the sensors all the time, including one in the spare if there is one. Just because a salesman tells you something, doesn't make it true. If you want real proof, ask them to pull up the TPMS codes on their Toyota computer and show you 5 codes programmed in the truck's computer. Until then, read the manual and it will tell you there is no TPMS in the spare. Or at least there isn't in the 07s.