I lost the owner's manual of 2008 scion tc. This flower vase shape light with exclamatioin point in the middle just came on. What does it mean?

Owners Manuals are nearly always free. Some repair manuals are free and some have a small charge to download them. Some give you a taster like this
https://www.onlymanuals.com/scion/tc/2007_toyota_scion_tc_service_repair_manual_pdf

https://www.google.com/search?q=2007+Scion+TC+owners+manual

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this may sound weird, your engine immobilizer system, may have taken a turn for the worse, first I would try to install a new battery, but if the transponder is broken, or defective, you will need the key number plate to have a new key made, this is done by going to your scion dealership, no tag, it is harder to do, sorry to give you the bad news, but maybe your local locksmith can help, I would call first

I am sorry but we have no wiring diagrams here. I suggest you find a local UHaul and seek assistance from them. You can also ID each wires function with a 12 volt test light and wire it up with that method.

never clean them, you will need to go and buy a new one

you shouldn't need plugs until 100,000 miles. if the engine light is on you need to run a scanner on the car to see why. something has failed like maybe an injector. parts stores will run scanner for free hoping you will buy the parts from them. what about warranty? drivetrain sometimes has longer warranty. good luck

Look in your owners manual in the guages section. It should tell you what the light represents.

Try Ebay,

It's the tire pressure warning light, you need to check your tire pressure on all of your tires.

the dealership has a special program that enables them to customize certain options such as the one you are talking about. But only the dealership has the capability.

This is already covered in the owner's manual, but here it is again as a quick reference.

Every 5,000 miles, a "Maintenance Required" light will blink for the first couple seconds after you start your car. It will continue to do so until it is reset. If it is not reset, than it will eventually turn on your "Check Engine" light. The purpose of the maintenance required light is to remind TC owners to change their oil. The factory recommended interval is 5,000 miles, but you can reduce the interval the light will come on to a mileage interval of your choice.

1. Before starting, make sure that the odometer is not on one of the trip mileage odometers but is displaying the standard odometer.

2. With the car off, press and hold down the odometer reset button. While still holding it, start the car.

3. The light should continue to blink for a couple seconds and than disappear. That will reset the light for another 5,000 miles.

4. The following are steps to change the interval in which the maintenance required light comes on. Right after you turn on the ignition while holding the reset button, you'll notice that the odometer display will show 5 bars. Each bar corresponds to a 1,000 miles. As each bar disappears, the interval will increase (0 bars = 5k, 1 bar = 4k). Release the reset button at the interval you desire.