Hello there, I own a 2006 Prius with 162,000 miles. I am pretty mechanically inclined and I have a question. Idk why the light is on. The oil is full and has always been, there are no check engine lights, both cooling systems are topped off and have been monitored for 2 weeks. I have also been checking engine temps and the engine is not getting hot at all. The large battery has been charged and is in good health. The 12v starter battery is also 2 weeks old. About a year ago and 12,000 miles ago the large battery took a crap. I pulled it, found two bad cells and replaced them. Since then I have had no battery issues. Even then the triangle wasn’t on. The light is now always on. Right when I start the car. Any ideas?
I checke d for codes and that’s why I’m kind of at a loss. When the light came on I was driving up a winding steep mountain road with a/c on and it was about 90 out. I assumed it was overheated. When I checked, the water was not boiling, mo steam. The car completely cooled and I checked coolant levels and they were good. I figured it got hot but was ok and cooled down. The car stars, runs and drives perfectly normal. Charging system as well. Is there anyway to reset the light?
Which OBD2 code reader are you using, as not all are toyota hybrid compatible. Have you checked the oil level recently, as the platform is know to eat oil at a high rate, especially at higher RPMs or freeway speeds.
The oil is full and was changed 2 weeks ago. The OBD2 I’m using may not be specific to the hybrid but I do know all the monitors are running and good. And there weren’t any codes. Also, I have used this OBD2 scanner on this Prius and it has worked for it. In the sense that it has picked up codes and helped me diagnose problems in the past. I wish I knew the exact possible reasons for the triangle. Over heating, low oil pressure, low battery voltage, etc...
If there is a red triangle, there should be codes, you may need to located another reader and scan again. Many auto parts shops have scanners that can be borrowed, try all of the retailers as each may not have a hybrid compatible scanner, even within the same chain. Many like to use a 'mini-vci' cable and a copy of techstream (dealer level tech software) to retrieve OBD2 codes (DTCs). You may also try an OBD2 bluetooth/wifi adapter and an App like Dr Prius, use this link to help with picking out a quality adapter : Hybrid battery diagnostic and repair tool for Toyota and Lexus From your description, it may be the inverter coolant pump (aka P0A93), have you inspected or replaced it recently? You can check for any dealer service history by running the VIN at : Welcome to Toyota Owners
Thank you for all of the advice. It’s a big help. I’ve never inspected the inverter coolant pump but I will. We have owned the car from day one off the dealer so I know it’s never had any previous work. Thanks again
Just thought of this. The water temps coming into the radiator are are accurate to what they should be and the temps leaving the radiator are good as well. Meaning the pump should be good. The engine is not over heating. If the inverter pump was bad wouldn’t the engine over heat?
Separate loops they are. Touch the pump with a finger, or a pencil/stick. Look in the inverter reservoir for movement. There was an inverter pump recall (or two), but most likely that has long since passed. The pumps only last about 100k on average.
Except for the things that light the triangle without codes. It's a short list but the problems that can light the master warning indicator without setting codes are low oil, low coolant, I think low brake fluid, and failed wiring at the HID headlight leveling sensor. The headlight problem also lights up an icon that looks light a headlight blinking. The OP has already ruled out most of these. The OP really needs to have the codes scanned with Toyota Techstream. It's very possible there is a code present that the generic readers are missing.
I know I need to maybe take it to Toyota so they can diagnose and codes. I still get no codes on my generic tester. I did check and the inverter coolant is pumping and moving and so is the engine coolant. Brake fluid, oil and coolants are all full.
I had a similarly strange error code on my 2005 Prius I talk about in this podcast episode. What solved mine is replacing (deleting actually) a corroded wiring harness located in the top of the cooling fan:
