I have a check engine and a (!) on the dash?

Post the trouble codes right here after having them read by a Prius-capable scan tool?

-Chap

 

Check your oil immediately...

 

how many miles on her?

 

At the start of the really cold spell here in the North East USA (early February 2015), ChuggyPig (my 2009 Gen II Prius) started showing the indicator you saw, and I put it down to the very cold weather and also the fact that the car had been sitting in a cold garage for a couple of days without being driven. I checked the tyre pressures and one of them was slightly low. I put air in the tyre, and re-initialized the sensors (p.377 of handbook) - hope this helps - Wil

 

I can't remember the emissions warranty in California, but the check engine light is usually emissions related. You should have someone read the codes to figure out the problem.

You might have a bad tire sensor, if the car can't pick it up, it'll show the (!). You can also have this checked and replace the one(s) not working properly.

 

Start w/ reading the DTC codes. If you don't have an OBD2 scanner (preferably mini VCI w/ Techstream), goto Midas or find an auto parts store that reads codes for free.

Intermittent CEL (Check Engine Light) could be P1121. When this 3-way cooling valve begins to go bad, the CLE can come on for seconds, minutes, hours, days, then disappear for seconds, minutes, hours, or days, and not in that order. And the cycle will repeat itself. If it turns out to be the problem, you can live with it, but you may be w/o cabin heat, as the valve might be stuck in the wrong position. You will eventually want to get the valve replaced.

Reset the TPMS as Post #5 says. It might also be one of the TPMS has gone bad/dead; getting the DTC read would reveal this.

How often do you check your engine oil level? If never or rarely, start check regularly; every gas fill-up, once a week, every other week, every other week, once a month, etc. You need to monitor how much oil your car is consuming and ideally keep the oil level as close to the top dimple mark on the oil dipstick. Ideally check the oil after the engine has been off for some time, allowing as much of the oil to drain back into the oil pan, for a more accurate reading. Also, the car should be on a level surface.

You are not allowed to post "My CEL comes on intermittently whenever I brake hard, take a turn hard, or accelerate hard? What could it be?" People who don't check their engine oil level report this.