I have an issue with my 08 Prius. Today while driving I noticed that the engine keeps running when stopped at traffic even though the HV battery was almost green and the AC/Heater was off (nice weather). Then a short while after that the alarm on with lots of dash warning lights. No red triangle though. The break became hard to press. Luckily the traffic was slow and so I managed to pull to the side. Turned the car off. Waited a few seconds and turned it back on. It ran fine after that. The car has 140K and got it at 130K. Did regular maintenance including spark plugs, trans oil, cleaned MAF sensor and throttle body. Also used Lucas to clean the ignition. Gas mileage has greatly improved. Today I registered 48MPG (295.3 miles by 6.159 gallons). I am thinking of the 12V battery since its seems to be the original Toyota brand but its reading normal based on my tests. The HV battery seems to working fine. Any help will be greatly appreciated.
Welcome to PriusChat!! Generally speaking when you have 'dash warning lights', you will have OBD2 codes (DTCs) stored in the ECUs (computers). Best if you can locate or borrow a toyota hybrid compatible OBD2 scanner, or visit an auto parts chain and have them scan it for free. The free scan they offer may not be fully compatible, but it could get you started in the right direction. Once you have scanned the vehicle and have recorded the DTCs, please post them in this thread and we can offer additional advice or direction. If you're interested in an OBD2 adapter to use with a phone App scanner like Dr Prius, be sure to visit this website first : Hybrid battery diagnostic and repair tool for Toyota and Lexus Many here will use a "mini-vci" cable and a copy of techstream (same software the dealer techs use), it requires a windows device.
Hi thanks a lot for your response. So currently there are no codes showing and it's driving fine. After I turned it off and turned it back on all codes disappeared and everything came back to normal. It's truly weird. Appreciate you recommending the scanner. I have being thinking of getting one but not sure which.
This incident might be an early warning sign that the HV battery is about gone. And.....very few 12 V batteries last 12 years. If it looks kind of worn and dirty.......like it might actually BE 12 years old, replacing it should be your first move. The quickest way to find something out would be to drive it to the nearest Toyota dealer the next time it fails......if possible. Most owners have no good way to tell the health of either battery, sometimes even with a code reader.
