Prius won't go into drive with red triangle on

Find or buy a toyota hybrid compatible OBD2 scanner, many prefer a 'mini-vci' cable and a copy of techstream (dealership technician software) installed on a windows device. Others may use an OBD2 bluetooth adapter with an App like Dr Prius, or Torque.

Once you have the OBD2 codes (DTCs), post them here for additional guidance.

Did you hear the HV battery fan running louder is the backseat passenger area?

How many miles on the vehicle, and did you replace the HV battery with a new OEM from the dealer?

 

You may have an issue with the HV battery again, if you didn't replace it with a new one in Oct 2019. But if you read the codes, it should tell you. 11.6v on the 12v battery is low, but shouldn't be low to the point where the car won't start.

If this was my car, I would first charge the 12v battery. Then read the codes on the car.

 

A high voltage leak is the only problem that causes that scenario.

Clear the codes with a reader or by disconnecting the 12 volt volt battery. With the codes cleared the car will drive normally even after the RTOD comes back on. Once you shut the car off it will not go back into drive or reverse.

 

What causes a high voltage leak? I have a 05 prius, doesn't go into drive or reverse, if I disconnect the two wire clips on top of the 12v battery for a few mins. It resets and then drives until I shut it off and try starting her up, then no R or D just N and P

 

The high voltage (hybrid) system is isolated from the car body. The most common cause of a leak is the hybrid battery. The battery modules can develop cracks that allow the electrolyte to seep out and establish a high voltage pathway to the car body. Other possible areas for leaks are the transmission, inverter, AC compressor, and cables.

 

Great information! What is the best way to find the source of the leak? I have the same issue. Started the car, went back in the house for a couple of minutes and returned as it shut off and had the RTOD.

 

This happened to me about a week ago also...I reset the batteries and the lights went away. Drove fine without issues up until tonight when it happened again.

 

You need to find out WHY the RTOD is coming on by scanning all the electronic modules (ecu) on the car for codes. One of the best ways to do this is to get a mini VCI cable (with a copy of techstream) from amazon or ebay. Techstream is the dealer diagnostic software. Install it onto an old windows laptop & you can retrieve codes and INF (sub codes) that give more details about any faults. You can also view data from any ecu and perform tests.

Posted via the PriusChat mobile app.

 

FYI Looked on youtube and figured out some testing. From the fuse lug on the hybrid battery I am seeing about 64v to ground so that's not good.

 

Thank you for the reply! Yes that is my next step, but looks like I may have found the issue with a leaking Dorman battery.

 

That also means the leak is 64 volts away from the point of measurement. That helps pinpoint which module is leaking. The modules crack in the recesses next to the mounting inserts. Don't expect to be able to see the crack or a pool of electrolyte. The cracks are just hairline splits and the leaked fluid is just a film. What will show is corrosion on the base of the battery.

 

Great info, thanks! When I got this car, the rear hatch had been left partially open and the sides were full of debris. Inside it smelled musty and I found about 3" of water in the spare tire recess and battery box. I cleaned it all up but didn't think about the hybrid battery. I removed it yesterday and when I took off the cover, found lots of corrosion on all the copper and evidence of moisture on the inside of the top cover. I will check all the batteries next week when I get time and disassemble/clean everything. Wondering if anyone has advice on how best to balance out the batteries, if I have to replace any...best tools?

 

Assuming there's one leak.

If there's more than one, 64 volts is the Thévenin equivalent voltage of the collection of leaks, taking into account the impedance of your voltmeter.

Another example of how problem solving can be kept much simpler by jumping on problems quickly (say, at the first sign of a leak and without giving time for others to develop).

 

So, today I disassembled the battery pack. All batteries tested between 7.81 and 7.87v. However, there was lots of corrosion.
As previously mentioned, this car had basically been rained in due to the hatch not being completely closed. When I removed the batteries, most looked like the picture attached. It looks like acid leaking down from the top of the batteries...Has anyone else seen this? Note, when you peel back the silver plastic, the corrosion flakes off and is powdery, like typical corrosion on a battery. But, I touched a tiny amount to my tongue and it did not feel acidic as from sulfuric acid. Could it be caused from just water in the cabin?

 

The electrolyte in these NiMH cells is potassium hydroxide, a very strong base, the other end of the pH scale from an acid. Instead of acidic and sour, it will feel more soapy. While it eats away your flesh just as effectively as a strong acid would. Go rinse that tongue of yours, be glad it still is all there, and don't touch that stuff again.

Get some boric acid at the store, mix up a saturated water solution of it, and use that to neutralize the electrolyte leaked in the battery while you are cleaning it up.

 

Measure for voltage between the module terminals and the mounting socket in the bottom of the battery. Also between the terminals and the corrosion. It's basically the same test you already did with the whole battery. You're search for the pathway of the high voltage leak. Is there any hot glue on the bottom of the modules on the opposite side from the mounting socket?

That battery is going to be a project to repair. It might be easier to start with a core in better shape. Use http://www.car-part.com

 

Thanks again for the reply, much appreciated!
I did some checking of the batteries to the metal base, but didn't see anything obvious as far as voltage. I did check some modules from the plus terminal to the corroded section of that module. From a quick check I saw a couple with .01v showing and another with around .49v so must be some leakage there somewhere. I have the base cleaned up with water/vinegar/baking soda mix and cleaned all the terminals as well as removed and cleaned the little metal tabs. Will this be sufficient or do I need to get some boric acid as mentioned above?

 

The vinegar would probably do the trick, more or less, but there's nothing gained by neutralizing it already with baking soda before it has a chance to neutralize the electrolyte.

 

Good point, thanks. FYI I found a couple of high voltage drainers...~5v and many others with around 1v. At least 10 that look bad for sure. Guess I need to look at replacing all.