high temperature coolant light -- technician is saying to replace the hybrid battery pack?

Ok I have some guesses:

Guess 1) are you sure the light is for coolant? The HV Battery is air cooled and has a fan that should get louder if it is over heating. Is it possible you just assumed it was coolant? P0A80 is often about the HV Battery, sometimes there are sub codes that tell which cell is failing, so you do not have to replace the whole thing. If you only had a location, we could advise about near by techs. Without a location, no one is near by.

Guess 2) There are two coolant loops, one for the engine, and one for the inverter, if it is the inverter that is over heating, that will not effect the engine. In the inverter coolant overflow, you should be able to see movement when in Ready.

Guess 3) any coolant over heating and battery failing are unrelated.

 

Sounds like there was a miscommunication somewhere, p0A80 is obviously a Hybrid battery fault.

If needed I would just source a Doorman replacement and go that route (3 yr warranty and much cheaper than the dealer).

 

If you are looking for a hybrid battery replacement I live in the bay area California and there are people that replace and refurbish hybrid batteries. I had a guy come to my house replace my hybrid battery, took my old one and put a refurbished one in there, turns out to be the guy was a retired Toyota mechanic as well. He was in and out in one hour and charged me $500 found him on Craigslist under parts section.

 

unfortunately, most of those repairs were probably not pertinent to your issue, although, who knows, may have been needed anyway.
probably time to cut your losses and look around for a younger model. you may wind up just pouring money into this car, trying to keep it on the road.

 

So from everything I've read, watched, and learned here on this forum, here is the quickest, lowest cost solution. of course its diy and frankly fairly simple, although its HIGH VOLTAGE. There are plenty of videos on how to do this but I'll give a mere brief description here.

There are 28 modules in your hybrid battery pack. Typically only 1 to 3 of them have failed. TMR-JWAP here on the forum is fantastic for replacing them for whatever you'd find them for on ebay and I believe him to be MUCH more reliable, based on my own purchase experience and his in-depth understanding of what you are currently going thru. If you have done other repairs that are similarly complex, this is cake really, you just have to be VERY careful. Do not connect/bridge any terminals with socket wrenches or anything metal!!


DISCLAIMER!!!!: THIS IS A DESCRIPTION FROM MEMORY NOT INSTRUCTIONS!!!! if you aren't remotely comfortable with doing this, DON'T!!!!
If you are comfortable, second guess yourself at every turn and ask(someone qualified, not me), ask and ask again. Always, always tell yourself, death from stupidity or accident is imminent. WATCH THE VIDEOS ON YOUTUBE. THESE ARE NOT INSTRUCTIONS, MERELY A DESCRIPTION. I AM NOT LIABLE FOR YOUR EFFORTS. ONLY YOU CAN PREVENT FOREST FIRES AND DYING!!!!!

ERRORS AND OMISSIONS ARE YOUR RESPONSIBILITY, NOT MINE. DIY AT YOUR OWN RISK. YOU ASSUME ALL RISK. WATCH ALL VIDEOS and gain all knowledge necessary BEFORE proceeding.

Disconnect your 12 volt battery in the back.

Pull out the panels and disconnect any white/black terminal clips

LOCATE THE LARGE ORANGE safety PLUG ON THE DRIVERS SIDE OF THE PACK and pull it out.

wait about 10 minutes for charge to dissipate (do not know if this is necessary but I always do it)

There are 2, roughly half inch orange wire harness ends, one pos, one neg. Disconnect one at a time using an electric screwdriver, 8mm long socket and keep a magnet handy to grab it as you get to the end of the unbolting. DO NOT touch the neg while unbolting the pos and vice versa. Do NOT use a socket wrench for this as you may drop it, earning a Darwin Award.

Tape each end of the wire harness off, and place the ends in a ziploc baggie, taped off and set aside behind the seatbelt.

Unbolt the battery from the car and place the 50 lbs or so on your work bench. Unbolt the covers and set aside. Undo the orange buss bars on each side using the same electric screwdriver and a magnetic 8 mm seating socket. do NOT use a socket wrench. Pull them all the way off and push far away from the pak.

There are 3 bolts that connect the computer assembly and buss bars to the rest of the pak. undo and pull away from the pak.

You will see the buss bars are orange plastic holding a bunch of copper mini plates. take them out of the plastic after fully clearing the pak and clean them with brasso or something like it. Set aside.

Get a multimeter with alligator clips!!!! and test each module. They should all be within 2 tenths of each other. There will be 1-3 bad modules that will typically test in the 6. something range. Mark the bad ones with tape. write down all the test results.

Pull the pack to the edge of your bench or tip it up on its side and undo the screws that hold the modules in place.
There are 8 large bolts that keep the pak together and 4 smaller bolts that hold the white plastic ends down. Whichever end your bad module is closest to undo the 4 large bolts clamping that side down and the 2 small nuts holding the large white plastic ends down to the chassis.

Pull the bad modules and replace, making sure to note those tiny wires which clip on the top and bottom of the pack. make sure you mark where those are supposed to clip onto when you reassemble the pack. There's 3 on the bottom and one on the top I think. See the videos. THIS IS A DESCRIPTION FROM MEMORY NOT INSTRUCTIONS. NOT INSTRUCTIONS. NOT INSTRUCTIONS.

Bolt the modules back in on the bottom and clamp them back with the big bolts.

Place the newly cleaned buss bar plates back in their orange plastic home.

Replace the computer assembly with the 3 nuts back onto the pak.

Connect the buss bars. carefully. Each nut should be lightly screwed down with an electric screwdriver and then finished off, CAREFULLY with a torque wrench to 48 inch pounds. DO NOT BRIDGE any two terminals with that torque wrench. This is the most focus demanding step of the whole thing. DEATH IS IMMINENT.

Place the black plastic buss bar covers on. Bolt the main cover on and carry the pak back to the car and put in its original position. dont bolt down yet.

Connect the two wireharness thats in the baggie behind the seat belt, one at a time. carefully. Clip all the white and black clips you had to undo to remove the pak. (If you decide to proactively maintain your battery pack with a system like Prolong, as i did, this is when you attach their wiring harness. the person who taught me how to do all this recommended I purchase it. it takes like 2 minutes to attach this harness at this stage.

its worth mentioning at this point that the cooling fan is located above the 12 volt battery well. Expose the cooling fan and clean Sparkling clean with a toothbrush and shopvac before proceeding.

Place the large orange safety plug by pushing in and DOWN. watch the video.

reconnect your 12 volt battery carefully.

check one last time that all the clips have been connected and are all the way in. If there is a P0AA code its because you didnt plug a plug in or its not all the way in.

Once you turn on the car and your dash is no longer a christmas tree marvel at a job well done.

now remove the orange plug and bolt the battery down and put the ecu cover on. put the orange plug back in. Re assemble all the panels and trunk assembly and you are good to go.

On average, with prolong you should get 1-2 years of driving out of this before having to replace another module. Note Dorman's pak has a 3 year warranty but i do not know how many miles that is. if its less than 60 k. you can do this yourself and including prolong your total expenditure should be less than 600 bux.

i just did this and well, im driving, getting 40mpg without hypermiling.

Jen here's the disclaimer again: DISCLAIMER!!!!: THIS IS A DESCRIPTION FROM MEMORY NOT INSTRUCTIONS. if you aren't remotely comfortable with doing this, DON'T.
If you are comfortable, second guess yourself at every turn and ask(someone qualified, not me), ask and ask again. Always, always tell yourself, death from stupidity or accident is imminent. WATCH THE VIDEOS ON YOUTUBE. THESE ARE NOT INSTRUCTIONS, MERELY A DESCRIPTION. I AM NOT LIABLE FOR YOUR EFFORTS. ONLY YOU CAN PREVENT FOREST FIRES AND DYING.

ERRORS AND OMISSIONS ARE YOUR RESPONSIBILITY, NOT MINE. DIY AT YOUR OWN RISK. YOU ASSUME ALL RISK. WATCH ALL VIDEOS and gain all knowledge necessary BEFORE proceeding.

Jen these are merely my musings on the subject. There are those on this forum far better than I to opine on all the ifs and whatevers. I did just do this however and am glad to offer the above merely as a way to provide some context for a DIY answer to your question. I'm sure there are errors above as I typed this at light speed. However, I am sure this can be done if one is FOCUSED, DETERMINED, EXTREMELY CAUTIOUS, and WILLING TO DO ALL RESEARCH NECESSARY b4 proceeding. I did, and it saved my life and thousands of dollars. I watched every youtube video on the subject and asked every stupid question.

Sincerely... and take all stuff seriously, especially that which is in RED!!!

AP

 

What does this coolant indicator light look like? I didn't think the Prius even had a light for that.

The code P0A80 will also light up about six or seven of the dashboard lights, including some that don't really have anything to do with the problem - the idea is to scare you into doing something about the hybrid battery *now*.

Dorman's warranty is 3 years, unlimited miles. And it's a reputable company.

I'm skeptical about the Prolong charger. Based on how batteries work, I rather doubt that it actually helps (and suspect it may even hurt - NiCad batteries should be cycled regularly). But I could be wrong.

 

Not exact, but amber is warning and red is STOP NOW.