2002 red triangle adventures

Dr. Prius only reads data from the hybrid battery, so I'd say that the good news might be that the triangle is probably not from hybrid battery issues.

But if there is a triangle, then there there are codes. Your "good code reader" probably only reads generic OBDII error codes. But then there are all of those "special" Toyota codes that they like to hide from you (and most code readers - sleazy corporate B.S.). For that you need a Toyota Techstream knock-off. Search this site and the rest of the web to figure that out. (You're looking for a Mini-VCI)

Before anything else, check the health of your 12V aux battery (in the trunk). Make sure you check it under load - like with the key in "Run" position but without the car in Ready mode. In Ready mode the hybrid battery will be sending it voltage. You need to see what the 12V does when it's loaded up by the car's modules, but not getting charge from the hybrid battery.

 

Josey is right, you have to have codes. Your tires have nothing to do with the problem. Since the light has gone on/off, I'd bet on the 12v battery as well. Most other codes stay lit.

If you happen to have a spare 12V battery, or just want to jump it from another car, you can do that to see if it solves your problem. Just put the spare in the trunk and jumper cable it to the original for the test. I have to add that thanks to a recommendation I got here, I replaced mine this week with a $22 lawn mower battery from Walmart - get the U1R so the terminals are on the right side. BTW, the lawn mower batteries weren't in the same place as the car batteries - a couple of aisle over at my Walmart. They also sell U1Rs at auto parts stores for a little more money. Finally, you have to rig the terminals, but it's real easy. If jumping it

 

My first Gen1 would randomly, it seemed, give me the triangle. Take it to the dealer, they find nothing wrong. A few months later, another triangle. Did that for several years. And then, the HV battery died. Replaced it and never had another triangle. Funny Rice U story (I went to UST): the Aggies fans chanting at a basketball game, "What comes out of a Chinaman's XXX? RiceRice RiceRiceRice."

Still hard to figure out how the tires have anything to do with it. Now, if you'd said wipers or floor mats....

 

My guess is actually going to be that the triangle was triggered by a dirty windshield. I'm sure there's a code for that.

 

That's the exact thing to do: get access to Techstream one way or another, read the codes. Things will be much less mysterious then.

 

Are you talking about the blue-colored "thermometer in water" light, towards the right side of the dash? That means the coolant is... cold! If you ever get a red "thermometer in water" light, that means it's overheating.

Story time: I live in Missouri, less than one mile from a freeway on-ramp. In the summer, the blue light in my 2001 sometimes comes on when I start the car in the morning, but it will be out before I get halfway to the freeway. In the winter, it will always be on in the morning, and usually doesn't go out until I'm at the bottom of the ramp, or a few tenths of a mile down the freeway.

Protip: Toyota Warranty & Toyota Manuals | Toyota Owners has a PDF copy of the owners manual. For free. Download it and read it while you are in the smallest room in your house; you will learn a lot.