Is it the 12v

Welcome to PriusChat!!

If you haven't already, tighten up the 12v cables to the battery.

How many hours per week do you drive the vehicle?

When was the 12v battery last replaced? (though don't last forever)

Somewhat related to the RToD, have you checked the engine oil level lately?

If there are warning lights displayed on the dash, then there are OBD2 codes (DTCs) stored in the ECUs (computers), many find it easier to retrieve the 'codes' from the 'computers' to assist in diagnosing the problem(s). Once you have the OBD2 codes, post them here in this thread for additional guidance and support.

 

YES. It could be the 12 V battery getting weak.
Or a connection becoming loose or corroded.

Get the battery tested......or if it looks old just get a new one.
Ask them to do the test twice.
If it is anywhere close to being questionable, then consider it bad.

AND just tightening the battery cable connections often is NOT good enough.
Unbolt each one, clean it off good and then re-attach.
Both ends of both cables.

 

These pictures of battery test should be after a full night's (10 hour) rest.

Posted via the PriusChat mobile app.

 

2 hrs a day should be enough to maintain a healthy 12v. It could be time to replace the existing 12v, or have it tested at a parts store.

Given the description, the engine revs louder, lack of power, it could be a failing HV battery.

Is the HV battery fan in the back seat passenger side audible or running at full speed?

Best to have the OBD2 codes retrieved with a toyota hybrid compatible scanner and post them here for additional guidance.

 

Stop jumping directly to the battery use the front jump point. Thats why its there.

Hatch is last place you want to be messing around in to jump a battery you reverse polarity that battery and your wallet will be in world of hurt. No reason to go in the trunk and 8 reasons to do all your 12 volt maintenance via the front jump point.

8 reasons because that's how many connections and a long cable under the car the 12 volt battery has to traverse to get to the front fuse box where it can do some work. When charging and testing up front you test all of those connections. Testing at that front jump would have immediately found a bad battery connection in the hatch.

The 12 volt battery is toast and the loud noise from the engine is most likely the hybrid battery has failed thats the red triangle of death your seeing and the car is in limp mode and you have to floor the car everywhere you go to get anywhere. Engine is now foced to make all of the power and that racket is the engine complaining becasue your flooring it. The bulk of power in the car comes from a healthy hybrid battery. .

Your not driving much anymore has killed both battery's. Your not alone there all failing including mine. Read all the posts on this forum.

use the search forums link up top and search

hybrid battery

for your repair options.

 

Good luck.
The sensor is there to detect a failure condition......like a failing catalytic converter.
Sometimes the sensor itself fails but sometimes it does it's job properly and the trouble really is something else.

 

Haven't heard of that App before, others have used Dr Prius or Torque. Check the build quality of your adapter before a trying more demanding App like Dr Prius, though Torque should be fine with your adapter : http://priusapp.com/obd.html

Many enthusiasts like to use a 'mini-vci' cable and a copy of techstream (dealer tech software) installed on a windows device.

Disconnecting the 12v for a period of time will clear the codes.

 

Wonder if the cat was stolen on previous owner and he threw in a cheap aftermarket cat and didn’t mess with the damaged cutoff sensor wires.

I would jack the car up and get under there and see if it has the OEM cat.
I just sold mine on eBay it sold for $1350.
Replacement cat was $125. Car actually runs better with aftermarket
Cat.

 

Sorry about that, as I thought all years of gen2 were supported. Hoping @jacktheripper has a moment to chime in on compatibility.

Is the OBD2 device you're using listed as having poor build quality? : http://priusapp.com/obd.html

Here is the workup for DTC P0038 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/2054m/cip0037.pdf

Here is the workup for DTC P0138 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/2054m/cip0136.pdf

 

12 volt doesn't cause any noises.

Shouldn't be any noises from the cat there usually trouble free stock. Unless its real loud and the cat has been stolen. Its epidemic on the west cost and few have been clipped in my area. Not sure about Orlando.

The 2 cats are right after the exhaust mani outlet. Theirs 2 of them the third one down is the resonator. They unbolt it from the mani and then cut it where it meets the resonator leaving the resonator dangling and the 02 sensor wires chopped off.

Pictures are phoyos of your 3 stock cats. See if those numbers in the pictures are on your 2 cats. if not the guy sold the oem cat which is worth $1350 on eBay right now and installed a cheapie aftermarket that is probably leaking.
Which is smart and what I just did but mine is not leaking. I also painted mine bright orange so if the thieves get under there they will see its not a stock cat its a cheapie.

Lots of shenanigans going on with G2 cats.

 

You can hope all you want but it isn't likely.
From your description, it sounds like you have an exhaust leak somewhere.
A bad one.

 

Sounds like your cat was stolen. Just look under the car about mid span and look for 2 dangling wires. That's the cut o2 sensor wires.