Red Triangle was intermittent, now constant

Hello all,

My wife has a 2004 Prius with around 185k on it that was intermittently displaying the Red triangle and exclamation point coupled with the on screen prompt, "Caution The transmission P lock mechanism is abnormal. Park your car at a flat place, and apply the parking brake completely." Following the on screen directions does not get rid of the warning.

Originally, it seemed this warning coincided with rainy/wet weather. However, recently the warning has now become permanent. I changed out the 12v battery with an Optima a few months ago (while the issue was still intermittent) hoping to address the issue, but it did not fix it. Using a generic OBD-II reader yields no fault/problem codes. Using a Mini-VCI and Toyota Techstream software shows the following codes: C0200, C0210, C1378, B1421, and C2310.

I'm a relatively capable DIYer, but I'm not sure exactly what I should be looking into from here. I have read tons of threads and posts around the net about the red triangle and cannot seem to get to what's wrong with mine. I was hoping to see if the community has a solution preferable and more cost effective than going to the local "stealership."

Any and all guidance is appreciated. If there's a thread someone can point to that I missed, again, I appreciate your pointing me in the right direction.

Happy New Year to all,

David

 

Thanks for the suggestions. I recently disconnected and reconnected the 12v to see if there was anything loose, but I'll check your suggestions tomorrow and post back. I also recently changed the oil, but I'll check that too.

Thanks,

Dave

Thank you for your reply as well! I will check and report back.

 

OK, so I checked the oil today and all is good there.

I checked the battery two different ways: by the on-screen display, and with a multimeter.

On-screen display reported the following:
Ignition: 11.4v
Ready: 14.3v

Multimeter:
Ignition: 10.84v
Ready: 13.85v

I also used the multimeter to check the 12v battery (though I didn't disconnect it from the car) while the car was off and it reported 11.88v.

I'm not sure what would make the battery crash like this over such a short period of time. Could a short somewhere in the car cause this?

In order to check the battery issue further, I'm going to swap it out with my father-in-law's from his 2008 Prius. I hope it's a simple battery issue and not a more complicated one. Please let me know if I'm on the right track or if I should be checking anything else.

Once again, I appreciate your help.

Happy New Year!

Dave

 

@ Patrick, I don't have a charger, but I'm sure I can get my hands on one to check and see if that works.

@bisco, I didn't check the voltage beforehand, so I'm not sure if it was faulty all along. But I do know that the issue with the red triangle and exclamation point went away after for a while I installed the new battery. It started to come back a few months ago on and off, and it has recently come back - permanently.

 

1. I'm picking up a charger today and will charge it overnight and tomorrow.

2. She drives under 500 miles per month.

3. (C0200, C0210) The car is a salvage, so there are any number of things that could be wrong. I cannot rule out an accident in the car's history, but I can rule out any accidents since we got the car. And the nature of the red triangle issue is that it crept up over time and finally became permanent very recently. I cannot make any connection between an event and the malfunction.

(C1378) Are the brake power supply and the wiring harness things I could swap out with another Prius in order to check?

(C2310) If I rule out the battery, are there simple next steps, or does this open a huge can-o-worms? Being that the car is a salvage, I don't want to just throw money at the problem.

Finally, I've not noticed any indication of flooding / water intrusion or even that of rodents chewing on the wires, etc. All of the wires seem to be in good, clean condition. The only issue I remember fixing recently was the driver side headlamp. I noticed the lamp was dimmer than the other, and then it started to go out every once in a while. I replaced the bulb harness and bulb which fixed the dim/out bulb issue.

If I need to replace the harness, is that a relatively easy job? Or should I just save some time and aggravation and take the car down to the local dealer to have them look at it.

Again, many thanks for your input.

 

I removed the 12v battery from her Prius to find this:

IMG_20151231_182611 by dsturchio posted Dec 31, 2015 at 7:13 PM

So, since I last checked the battery (sometime over the summer) some water did indeed get into the car. It was only about 1/4" deep and the battery showed no signs of damage. No puffiness, no punctures, no discoloration or marks on the casing that would signify a blow up of sorts. There's no mass of crud around the terminals either. But there was liquid in the battery bay which had never been there before. I wonder if something spilled in her car and made its way into there.

I cleaned up the liquid, and I now have the battery on a 12v charger. The charger didn't report that the battery was faulty and needs to be replaced. I'll check and see it's status in the morning.

I'll report back after its charged up and reinstalled.

Happy New Year

 

The battery read charged about an hour ago, so I took it off the charger and reinstalled it. I forgot to write down the voltage before installing, but I remember it was higher than it was yesterday.

After the install, I cycled the power on the car a few times and took it for a ride around the block and the red triangle remains. I checked the battery when I got back to my house and it read 12.54v.

I then ran Techstream to see if there were any changes in the codes and I pulled the same exact codes. In total I probably drove the car for about 3 minutes and then ran the car in ignition mode for about 15 minutes while I messed around looking through techstream.

I also reread the volts as I did originally:
On-screen display reported the following:
Ignition: 11.9v
Ready: 14.0v

Multimeter:
Ignition: 11.98v
Ready: 14.10v

I'm not sure where to go from here except for swapping out the battery and the brake power supply from a known "good" Prius.

I'll update again when I've done that.

 

I cannot seem to find out how to clear the DTC in techstream. Or do you suggest using a different program?

Update: I just changed the resolution on my laptop (I'm emulating WinXP through a Macbook) and I was able to see the rest of the program window - one particular button being the clear DTC button.

I successfully cleared all of the codes except for the B1421, which has to do with the Air Conditioner, and the C2310. I'll scour the forums again to see if there are any solutions. If you have anymore suggestions, send them my way. Thanks for your continued input.

 

I'm set to go tomorrow to swap out some components to see if I can narrow it down. I found in the shop manual and pics from another post that the transmission control ECU is located under the glove box. I'll inspect the wires, clean up the contacts and swap out everything possible with my father-in-law's Prius. Hopefully it's something easy and I'll be back in business soon.