2005 Prius - Red Triangle of Death Troubleshooting

Writing this post more as a log of my own issues and my troubleshooting steps. There are lots of good posts on this forum, but I thought I'd add my own troubleshooting experience.

Mileage: ~95000
Issue: Driving home from a business trip. 1.5 hours into a 3 hour trip. In the rain on the highway. Cruise control is on and I am going up hill at around 75 MPH. All of a sudden the cruise kicks out and all lights kick on -- red triangle, VSC, check engine, (!). After I crap myself, I slowly pull off at the next exit and turn off the car. At this point, I am 90 minutes from home at 6:00 PM. I start trolling this forum and see lots of issues, but for my immediate situation, it seems everyone kept driving it, at least minimally. I check the oil to make sure its not empty. It's in between the 2 dots, so I press on. The VSC and (!) are no longer on when I restart.

Car drove fine at 65-72 MPH all the way home. The VSC and (!) did come back on, but I did not hear or feel any difference in driving experience.

This morning I changed the oil. It was overdue as I was at about 7500 mi. since the last one (I use Castrol synthetic high mileage). I also tested the 12V battery as that was an easy check and it was good. 12.4V.

So, next steps:

1. Get the code checked. Some posters said the lights went away on their own. I plan to stop by my local parts store, as the nearest Toyota dealership is 40 minutes away. I assume it will return nothing, but I can always hope. I will share the results of that once its done.

Other notes:
* I have noticed my mileage dropping with the weather. I bought the car last Spring, so I thought maybe it was the cold weather (though my Prius is always garage kept). Wondering if it is something else.
* Other posts point to the wetness of the roads, the inverter water pump, battery pack, and transmission. I will wait and see.

Today is Saturday, I will let it "rest" today and take it to the parts store tomorrow.

I am not much of a mechanic, but am looking to learn, and always willing to try new tests and troubleshooting ideas, esp. if there is a YouTube video ;-)

More updates to come.

 

Status update: Just returned from my local O'Reillys. They read the code(s):
C1241
C1300
C1357
PA093

The C1300 and esp. C1357 seem to point to the battery pack, which would align with my mileage issue, I think.
O'Reilly's quoted me a new battery pack for $1417. Another thread recommends a greentec battery pack with a 4 yr warranty for $1600

And this post spanning over the past 6 years and 121 pages discusses testing each module and recharging/balancing them:
gen-ii-prius-individual-battery-module-replacement.125588/

My short-term plan, unhook the 12V battery lead, wipe out the codes, and see how fast it comes back. I also plan to test the voltage of each module when it does.

If anyone with any experience is reading this, I'm looking for feedback:
* Is it worth going to a dealership to make sure I have the right codes?
* When it comes to recharging or swapping out modules/cells vs. buying a new battery pack, where does the payoff end? I have a standard trickle charger, but would probably have to buy charging equipment.

Thanks

 

Thank you for the quick response!

I just bought this vehicle in the Spring. It only had 80,000 miles on it and the previous owner took very good care of it.

If you have any recommendation on YouTubers or people that have documented steps on how to test & replace, I'm interested.

 

Just an update to my situation. After resetting the 12V battery and clearing the codes, I purchased the Dr. Prius app for my iPhone (and I forked over the $30 for the mechanic version), as well as the Veepeak OBD2 BLE ELM27-compatible scanner ($25 on Amazon). Totally worth it. It told me that my that battery level was still in pretty good shape. So I did nothing for a while.

Last week, the red triangle of death came on again. About 95K mi. on it at this point. Weather was clear and roads were dry, unlike the the last time my dashboard lit up like a Christmas tree. I plugged in my Veepeak and it threw the P0A93, but nothing else. Based on the comments from @davecook89t and @TMR-JWAP, I'm going to give it a go to replace it. So thank you both!

Thanks again for everyone's advice. I will continue to update this thread on my little Gen II.

 

Realized I never followed up. This summer, I finally dedicated a Saturday to replacing the inverter coolant pump. The red triangle was flashing every time I drove the car more than 15 minutes in the summer heat. The new pump worked like gangbusters. After researching several ways to do it, I settled on a youtube video of a someone that explained it very clearly. After using his tutorial, as well as doing a coolant flush (also a youtube video), it ran flawlessly! No more red triangle!

One recommendation: If you are replacing the inverter coolant pump, take the extra 10-15 minutes to take off the front fender and the headlight. It's a pain in the nice person, I know, but it's easier than shredding your hands trying to reach down in there. And it probably would have been faster since I already knew how to do that. Otherwise, it's not very accessible.

Call this one closed. Thanks to everyone for their help!