Red triangle! Car won't go into 'Ready' Mode

Once you get a code reader capable of reading the codes that are there (or have them read by somebody who has one), the picture will become clearer.

 

Hello all! So last week while driving I got the dreaded red triangle warning and when I parked and turned off the car and tried to start it again my dash looked like the picture I attached!

That always stinks.

I Checked for codes and nothing came up on the code reader!

Apparently your code reader is not adequate for hybrids like the Prius, because codes are there.

I did lots of research and searching and everyone seemed to say ‘replace the 12v battery’ so I did that and the car started once and I turned it off and tried starting it again... now same issue is happening and won’t go into ‘Ready’ mode...

That's because many people instantly jump on the 12v battery as being the problem. Sometimes it is and most times it's not. Never hurts to test it, but hurts about 200 bucks to just go replacing it as a crapshoot solution. Somewhere in your research you may have seen that this is clear evidence that you have a high voltage insolation fault. I would bet that if you disconnect the 12v battery again, it will let you go ready. Once the code comes in again, and you turn off the car, it won't let you restart it again. (unless you disconnect 12v power again)

any help would be much appreciated!!

You're welcome.

When I changed my battery there was some water at the bottom, maybe a half an inch or so, does that mean anything?

It means you probably are leaking water into the car from the area around the edge of the hatch seal. There's a few body seams in that area that tend to get small cracks and start leaking.

 

It means you have a leak. Fix it before rust becomes a problem. Check the ground from the battery for corrosion.

 

Yes. The HV isolation fault kicked in again, so it probably won't go ready again until you disconnect the 12v again. Hopefully it's not the transaxle failing, but the only way to know for sure is to get the codes and subcodes .

 

Unfortunately, any time you disconnect the 12v battery, it resets all codes. Along with that, even if you have the RTOD on the dash, many code readers aren't hybrid compatible and they won't pick up those codes. If there's a check engine light, which is for the more generic ODB2 codes, they'll read that, but not the hybrid codes.

You may need to just call a few different auto parts places that do free code scanning to see which one's can check hybrids. Then hope the RTOD pops up while you're driving there.

 

The codes that have a snowflake next to them have freezeframe data. If you click on the snowflake, it will display that data. Post a photo of that data. Many times there is a line item labeled +B or something similar. That's the 12v. What is it showing?

 

You have a lot of Uxxxx codes which are various communication problems. You can click on the little blue snowflake icon next to the U0121 and U0124 codes and post up those images.

I don't think you have said what code readers you tried, but if any of them were Bluetooth dongles, after clicking on the snowflakes, I'd be inclined to clear all codes, do a couple of drive cycles and then scan the car again.

[EDIT] posted at the same time as TMR-JWAP. LOL.

 

Just saw this thread. I thought TMR-JWAP was correct with the isolation fault diagnosis. Then you got all those U codes. I have seen that before. It always led to replacing the Skid Control Computer. It is also know as the ABS Computer.

That computer is located just above the gas pedal. It's held in with three nuts. The bottom two are not too bad to remove. The top nut is just below the speedometer and is a bear to get to. These computers can be bought cheaply at local junk yards. Use Car-Part.com--Used Auto Parts Market to find one. It is possible to unplug the original computer and plug in the replacement without removing the original. Techstream is needed to initialize the new computer.

 

I would sooner or later troubleshoot the P0AA6 ... that's a real condition, and while one voltage leakage path isn't such a big deal by itself, it's not advisable to let it stay unaddressed long enough for a second one to form and complete a circuit.

I'm not saying it's related to the other codes; there may be other problems. At the same time, the loss of isolation between the high-voltage system and the body ground could possibly couple electrical noise from the one system into the other and have some influence on comm errors. Not something I've definitely seen, but wouldn't rule it out.

 

It appears your car has two separate faults happening at the same time. All the U codes point to the ABS computer. They are available for $50 and you can have a replacement in the car in an hour. So that's not a car killing problem.

For the P0A66 try this test. Be more careful than the guy in video. Wear gloves and use an alligator clip to hold one of the test leads.

 

I guess I'm not understanding this test. The multimeter in the video had wandering voltage whether his probe or connect to anything or not

 

The wandering voltage is only millivolts. Some meters just do that. The point is the reading for a non leaking battery will bleed down to close to zero volts. If the battery has a leak the voltage reading will stabilize.