Last post on May 04, 2012 at 7:57 AM
You are in the Toyota Highlander
What is this discussion about?
Toyota Highlander, SUV
#5 of 11 Re: Yellow Exclamation Point Error [martyjk]
Mar 22, 2007 (3:28 pm)
I may be wrong but I thought I read somewhere that the way that system works is by detecting any difference in the RPMs of each wheel. I know that when I did have a flat, the entire time we had the spare on the car that light kept coming on. I was told that was because of the fact that the spare, which I had not rotated and was still new, was larger and rotating at a different rate than the other wheels.
I could be way off on this, but that was my understanding anyway.
#6 of 11 Re: Yellow Exclamation Point Error [billran]
Mar 22, 2007 (3:41 pm)
Nope, the Tire Pressure Warning System, checks pressure.
From TW-11 of Toyota Camry Service manual ......"A tire pressure warning valve and transmitter is equipped with a tire pressure sensor and a transmitter and installed in a tire wheel assembly. The sensor measures the tire pressure. The measured value and transmitter ID are transmitted to the tire pressure warning antenna and receiver......., the ECU compares the measured air pressure value with the standard value. When the value is less than the standard value registered in the tire pressure monitor ECU, the warning light on the combination meter comes on."
By the way as a tidbit, these batteries in the sensors are supposed to last approximately 5 years.
#7 of 11 Re: Yellow Exclamation Point Error [kiawah]
Mar 22, 2007 (6:58 pm)
Thanks, it may be that different Toyota Models use different methods. I did some searching and found the explanation below in another fourm. I can't say for certain it is accurate but I believe thats where I read it initially. Not saying your explanation is wrong, just trying to figure out where I got the idea in the first place.
http://www.tundrasolutions.com/forums/highlander/77665-2006-highlander-low-tire-- - - - pressure-indicator/
The Highlander uses an Indirect Tire Pressure Monitoring System versus Direct type.
There is no transponder in the air valve. The H/L uses a plain tire old valve. Thus, there is no PSI reading done by this Indirect Type System. It uses the ABS speed sensors to calculate differences of tire rotational speed among the Four rolling tires(the Spare is not included).
When the spare tire is put on, say when yu get a flat tire, the TPMS button must be pressed. (Recalibrated)
Direct Type TPMS costs more for Toyota and only puts it on select models. But for Toyota, the Indirect System meets DOT's TPMS mandated minimum Requirements for 2007 vehicles.
The Direct type system uses a transponder/PSI reader type Air Valve on each tire(including the Spare). Each of the 5 tires send a reading of the PSI to the reciever in the Vehicles TPMS ECU. It has a small battery and is self powered. Battery must be replaced when yu replace your tires. It must be carefully mounted. Each tire has it's owner frequency channel and ID. for it to be recognized by the ECU. This system is more precise. But has it's own set problems as a result.
#8 of 11 Re: Yellow Exclamation Point Error [billran]
Mar 22, 2007 (7:34 pm)
Wow, okay, never read of that TPMS approach being utilized, seems that might trigger going around a curve. That's a clever approach however, given it utilizes existing sensor pulses already on the vehicle. Perhaps that approach needs an extended time of the revolutions not matching. I don't have the manuals for a 2005 Highlander to give definitive answer.
#9 of 11 Re: Yellow Exclamation Point Error [kiawah]
Aug 11, 2007 (9:11 pm)
I'm brand new here, as of 15 minutes ago.
I just wanted to express my surprise and delight to find this forum. After a dozen or more years on the Internet I should think to do a WWW search any time I have a question on any subject. Sometimes it takes a while to occur to me.
I have a 2005 Highlander, purchased in January, 2004. It has 16K miles on it. (No snickering; I'm old, OK?)
I had my first flat tire last week. There was a time when I would have put the spare on myself, but why do I pay AAA dues if not to spare me the dirt and aggravation?
I took the flat to the only tire shop in this small, desert town and picked it up the next day. The spare is still on the car. (I was pleased to notice that the Highlander has a full-size spare. However, I'm not sure I could have found and deployed it without referring to the Owner's Guide.)
The TPWS light came on at some point after the spare was installed; I'm not sure when.
Due to the poor organization of the owner's manual it took me 20 minutes to find the information about re-setting the system. The illustration was so poor that I was looking for the button on the steering wheel ... then the dash below the steering wheel . . . finally under the dash, where I found it. Just those three little words, "under the dash", would have saved me another five minutes.
Imagine my surprise when the light came on again after about a half-hour of driving. Several re-sets have had the same result.
I'm due for regular service (I use the dealer in a nearby town), so I guess I'll let them handle it. However, I wanted to understand the system before dealing with them.
The two theories as to how the system works have me intrigued.
If an RPM sensor were used, then there would have to be some sort of averaging system to preclude the false errors when turning a corner.
I'm also wondering whether either system would be easier to design to handle over-pressure as well as under.
#10 of 11 Re: Yellow Exclamation Point Error [bluesbassdad]
Aug 12, 2007 (6:13 am)
I would check to make sure the pressure in all 5 tires are at the right pressure. I'm assuming that the original flat was plugged, is now at pressure, and in the car, right?
May 04, 2012 (7:57 am)
Thank you all. This forum saved my day. Just had a yellow warning today morning. Google search lead me to this forum. And ban I found the nail.