Hello, I have a 2005 Prius. I have been getting normal gas mileage and haven't seen any new issues. However, the red triangle and check engine light both popped on. I took it to a shop that checked the code and he said that it was odd because no codes were popping on. He said that he had heard about that happening to people when the 12v is going bad. I took that out, and took it to the shop. It was in fact bad, so I changed it. The light stayed off for 24 hours. Then, they popped back on. I'm not sure what is causing it. The pink fluid is moving and looking good. The gas mileage was in the mid 40s today. I should mention that I have been keeping a watchful eye on it since this happened and have noticed that the traction batter indicator seems to be going into the green more frequently. I also noticed that when I was driving today, I pulled over for 4 minutes and when I got back in, the battery on there had gone down. I don't know if I'm noticing something that isn't there, or what to be honest, but I thought I should bring those things up. Any ideas?
Crap equipment. Crap shop? Rest assured. Lights = codes, esp the master warning light (red triangle). Is the engine oil level between the Full and Low marks on the dipstick? Keep the engine oil level closer to the FULL mark; NEVER OVERFILL. Check the engine oil level with regularity: weekly, bi-weekly, every gas fill-up, etc. The more frequent, the better. How did you determine the 12V battery was bad? Irregardless, you now know the 12V was NOT the cause of the warning lights. Stop guessing. Goto a modern auto shop and pay to have the codes read. A Toyota dealer will definetly have the equipment (Techstream software) to read ALL Toyota/Lexus/Scion/Daihatsu codes! Goto a shop that specializs in Toyotas; they will probably be using Techstream too. Any other auto shop then the first one you went to. Midas, AutoZone, O'Reiley; they read for free, but lack Techstream software, so they won't be able to read ALL codes. Report back with all codes retrieved.
Anyone who owns an old Prius should consider owning a few tools to help them diagnose their car. - Android phone/tablet - Torque Pro app - Elm Bluetooth OBDII adapter Altogether these three item will cost you less than $100 and you will use them over and over to see live data or read codes from the car.