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Red Triangle was intermittent, now constant

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by dsturchio, Dec 30, 2015.

  1. dsturchio

    dsturchio Junior Member

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    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
     
  2. JC91006

    JC91006 Senior Member

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    make sure your connections to the rear brake controller (next to the battery) is plugged in and secure. Then double check your 12v voltage is good 12.5v+. You should also check your oil level too
     
    #2 JC91006, Dec 30, 2015
    Last edited: Dec 30, 2015
  3. edthefox5

    edthefox5 Senior Member

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    Do you mean the brake battery back up supply?

    I think Jc is correct. The codes you pulled are all thrown when the 12 buss dips very low. Even though the battery is new I think your still chasing a 12 volt issue.

    Get a good digital voltmeter. Push the ready button twice without your foot on the brake and that puts you in Ignition. The car should be in ignition not ready. Measure the 12 volts across the battery jump points under the hood and ground. I suspect its very low like 10.8

    Then after measuring it push the ready button with your foot on the brake and make the car ready. Measure with voltmeter again same place. It will reveal the charging voltage. With a really low battery the charging voltage will be max like 14.4.
     
    #3 edthefox5, Dec 30, 2015
    Last edited by a moderator: Dec 30, 2015
  4. dsturchio

    dsturchio Junior Member

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    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.
     
    #4 dsturchio, Dec 30, 2015
    Last edited by a moderator: Dec 30, 2015
  5. dsturchio

    dsturchio Junior Member

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    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
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I think you would be better off by just charging your 12V battery overnight with a max 10A charger. Then see what happens.
     
  7. bisco

    bisco cookie crumbler

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    it's hard to say if the battery was marginal when you got it, or what might be going on. did you check the voltage before installing?
     
  8. dsturchio

    dsturchio Junior Member

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    @ 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.
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Make sure the 12V battery is in good condition by fully-charging it. The voltage readings that you reported show a battery that is partially discharged.

    2. How many miles does your wife currently drive the car, per month?

    3. The fault codes that you reported indicate several problems:

    C0200: right front speed sensor
    C0210: right rear speed sensor

    Both of these indicate a problem with the wheel sensors on the right side of the car. Either the sensors are bad, or the wiring harness is bad. Was the car in an accident on that side of the car?

    C1378: capacitor communication circuit malfunction. There may be a fault with the brake power supply (large black rectangular housing, located next to the 12V battery) or the associated wiring harness.

    C2310: open or short circuit in BATT. This terminal is supposed to receive constant 12V. This DTC means the transmission control ECU sees voltage of less than 10V for one second or more. This is why you need to make sure the 12V battery is in excellent condition with a full charge. That caused the intermittent MFD warning that you had been noticing about the transmission parking lock.

    If there is any possibility that the car has been exposed to damage from, for example, rodents chewing on wires - or flooding, that could cause the issues you have reported.
     
  10. dsturchio

    dsturchio Junior Member

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    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.
     
    #10 dsturchio, Dec 31, 2015
    Last edited: Dec 31, 2015
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. If you are going to buy a charger, get one intended for AGM batteries which require a higher charging voltage vs. normal flooded cell batteries.

    2. 500 miles a month is very low usage, so I suggest you definitely need to charge the 12V battery now, and also consider charging the battery at least once per month to keep it reasonably charged in the future.

    3. You can easily swap the brake power supply. You cannot easily swap the wiring harness.

    If you decide the wiring harness is at fault, the dealer's remedy will be to replace the harness. That may be very costly, into four digits.
     
  12. bisco

    bisco cookie crumbler

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    when you change the battery, you might reset the codes. maybe it took awhile for them to come back.
     
  13. dsturchio

    dsturchio Junior Member

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

    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
     
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The most likely reason for water accumulated in that area is a crack in the right hatch seam. The seam is hidden by the black plastic trim which runs along the roofline from the rear to the front of the roof. That trim can be easily pulled up, for inspection.

    Since this car has a salvage title, it is certainly possible that accident damage was not properly repaired, leading to this water leak.
     
  15. dsturchio

    dsturchio Junior Member

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    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.
     
  16. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Use Mini VCI to clear the DTC, then see whether the same DTC reappear.

    Check the wiring harness connector to the brake power supply. If you see any corrosion you will need to clean that off. Use electrical parts cleaner spray which you can usually buy at an auto parts store.
     
  17. dsturchio

    dsturchio Junior Member

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    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.
     
    #17 dsturchio, Jan 1, 2016
    Last edited: Jan 1, 2016
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

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    You don't need to worry about B1421 which relates to the AC solar sensor. Regarding C2310, you would have to find the transmission control ECU and locate the BATT terminal to see why the battery voltage is low there.
     
    dsturchio likes this.
  19. dsturchio

    dsturchio Junior Member

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    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.
     
  20. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Pin 13 on connector T4 is the BATT terminal, and is supposed to have 12V at all times. After you locate the ECU and that connector, measure the voltage on that pin and see what you get. Also inspect that pin in particular, for corrosion or some other fault.
     
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