1. Attachments are working again! Check out this thread for more details and to report any other bugs.

2009 Warning Lights Will Not Turn Off, Even when Faults Cleared

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Zapman, Sep 9, 2018.

  1. Zapman

    Zapman Junior Member

    Joined:
    Sep 15, 2016
    12
    7
    1
    Location:
    Ohio
    Vehicle:
    2009 Prius
    Model:
    Five
    Hello all,

    This has got me stumped. I have multiple warning lights, but the Techstream software found only 1 fault that had to do with an oxygen sensor. All the warning lights stayed on, even after clearing faults with the Techstream software.

    Red Brake light also on, though fluid level fine. Car seems to run and drive normally. No issues with braking, or engine.

    Any ideas?

    Thanks in advance,

    Zapman
     
    #1 Zapman, Sep 9, 2018
  2. hchu1

    hchu1 Active Member

    Joined:
    Sep 28, 2006
    316
    127
    0
    Location:
    Houston, Tx.
    Vehicle:
    2014 Prius v wagon
    Model:
    Two
    How is the 12v aux. battery?
     

    Attached Files:

    #2 hchu1, Sep 9, 2018
  3. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,323
    15,108
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    It's very common for people who are using alternatives to Techstream to post about having "no codes" when they have warning lights on. It is much more peculiar to see that if you are using Techstream. However, it should be able to provide a wealth of other information even if for some reason it isn't showing you codes. What version is it, and what are you using for a dongle?

    Can you post screenshots of the Data List screens for a few of the ECUs? Maybe the brakes, for starters, since you mentioned a brake warning light.

    -Chap
     
    #3 ChapmanF, Sep 9, 2018
  4. Zapman

    Zapman Junior Member

    Joined:
    Sep 15, 2016
    12
    7
    1
    Location:
    Ohio
    Vehicle:
    2009 Prius
    Model:
    Five
    Here is the only code that came up.
    I replaced the 12V Aux battery about 6 months ago.


    I had an issue in the past with the old battery getting weak and throwing all kinds of phantom codes, but never had the lights stay on after clearing the codes.

    I should add the car is not driven often. I try to take it for a spin (about 5 - 10 miles) about every month. My son is away at college, and he drives it when he is home.

    Thanks,

    Zapman
     
    #4 Zapman, Sep 10, 2018
    Last edited: Sep 10, 2018
  5. Zapman

    Zapman Junior Member

    Joined:
    Sep 15, 2016
    12
    7
    1
    Location:
    Ohio
    Vehicle:
    2009 Prius
    Model:
    Five
    I will try to pull the Aux battery tomorrow after work, and charge it, to see if it really could have gone bad already. It is an Optima Battery made to fit the Prius.

    I wondered if there was a relay that could be stuck or a ground could have gone bad causing the lights to stay illuminated, when they shouldn't be.

    Zapman
     
    #5 Zapman, Sep 10, 2018
  6. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,323
    15,108
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Hmm, well, here's a thing sort of jumps out at me: that screenshot you've posted only even shows four of the car's computers: Engine & ECT, Hybrid Control, HV Battery, and Cruise Control.

    There are at least twelve computers in your car: those four, plus steering, skid, gateway, transmission control, transponder key, meter, body, A/C, and Power Source. Thirteen if you also have smart key. These are the ones in the 2004 book ... by '09 there might be even more, depending on your option level. Hm, I almost left out the ones on the AVC-LAN: the MFD, and nav, if you have it.

    There are at least eight, nine, ten computers in your car that Techstream is showing you absolutely no information for. It is not even saying it failed to contact them. It is acting like it has no clue they are even supposed to be there. This I have not seen before.

    What version of Techstream is this? What are you using for a dongle? And what did you tell Techstream you were connecting to, in the start up connection dialog?

    The codes for the warning lights that won't go out are being reported by one or more of those computers that are absent from your Techstream health check. This is what usually happens to people who are using generic, non-Techstream readers. (At least the generic ones have an excuse ... they honestly don't know any other computers are supposed to be there.)

    Ehh, that gets said a lot here, but if "phantom codes" is ever going to mean more than "codes I assumed were meaningless because I didn't know what they meant and they didn't come back right away when I blindly cleared them", the evidence bar has to be a little higher. A code is genuinely bogus if: it gets retrieved, it gets looked up to understand what its detection condition is, and that detection condition was demonstrably not present when the code was set. That there would be a bogus code. Short of that, there are just codes folks choose not to follow up on.

    -Chap
     
    #6 ChapmanF, Sep 10, 2018
  7. Zapman

    Zapman Junior Member

    Joined:
    Sep 15, 2016
    12
    7
    1
    Location:
    Ohio
    Vehicle:
    2009 Prius
    Model:
    Five
    I took out the aux battery, and it measured at 10.9V! I am charging it overnight to see if it will take a charge. Low aux battery voltage could be causing my issues. By the way, by "phantom codes" I mean warning indicators that go away with an aux battery fully charged.

    When the last battery was starting to go, I had a ton of error codes. After installing the new aux battery, and clearing the codes, they did not returned, at least until now that the aux battery voltage is incredibly low.

    Thank you for your assistance.

    The old laptop I use to run the software died, and I am recharging that battery too, so I can't ID the version of the software I am using.

    The software and interface cable was obtained through a seller on a popular auction site.
     
    #7 Zapman, Sep 11, 2018
  8. Zapman

    Zapman Junior Member

    Joined:
    Sep 15, 2016
    12
    7
    1
    Location:
    Ohio
    Vehicle:
    2009 Prius
    Model:
    Five
    Software version 10.30.029. Battery fully charged. Ran software again and cleared errors except two. RH Rear Wheel Sensor and an Oxygen Senor (2). Red Brake light still lit, with apparently no related codes, unless the wheel sensor being out would trigger it. Brake fluid level half way between full and minimum. I topped it off with no change in the warning light.

    Is there a way for me to read a code for the brakes others than using the version of the software I have?

    Thanks!

    Zapman
     
    #8 Zapman, Sep 12, 2018
  9. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,323
    15,108
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Brake codes can be read by the Tc-to-CG jumper, count-light-blinks method, takes the scan tool out of the loop.

    -Chap
     
    #9 ChapmanF, Sep 12, 2018
  10. exstudent

    exstudent Senior Member

    Joined:
    Jul 11, 2009
    2,212
    900
    0
    Location:
    Torrance, CA
    Vehicle:
    2007 Prius
    Correct; CAUSE-EFFECT.
    The brake light is still lit b/c there is a problem. If the ECUs did not detect a problem, the brake light would NOT be lit. If you cleared all codes and the brake code came back immediately, then there is a problem somewhere. Maybe a creature chewed on the wheel sensor wire?

    Techstream ver10 is more than adequate to read the 2009. I'm on ver8 for my 2007.

    Lack of regular use will discharge the 12V battery, and is not good for the HV Battery.
    Driving 5-10miles once/twice/three times a month will NOT recharge the 12V battery. The Gen2 Prius 12V bus only puts out about 4amps. Better to just make the care READY and lit it sit for hours (say 24).

    Best to get a smart AGM compatible 12V battery charger. A non-AGM compatible charger does not recharge to a high enough voltage and will cut off prematurely b/c it things the connected battery is fully recharged, when it is not. Post #5&#8 have some useful information on testing the Prius 12V battery and smart AGM chargers; Is my inverter coolant pump slowly failing? | PriusChat

    Why not just drive the Prius periodically? Twice a week to work? Once a week or every other week?
     
    #10 exstudent, Sep 12, 2018
  11. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,323
    15,108
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    I'm doubtful of that figure. AHetaFan measured an order of magnitude more going into the aux battery when it was low on charge. That was a Gen 3, but did the DC/DC converter behavior change all that much Gen 2 to Gen 3?

    The figure of 4 or 5 amp charging may come from the recommendation on the battery label. Maybe it is close to what the charging current really is if the battery is near full charge. But before Gen 4, the car doesn't really have a current sensor located at the battery, and really just regulates voltage. As AHetaFan's readings suggest, that can mean that at low states of charge, it significantly exceeds the current recommendation on the label.

    -Chap
     
    #11 ChapmanF, Sep 12, 2018
  12. Zapman

    Zapman Junior Member

    Joined:
    Sep 15, 2016
    12
    7
    1
    Location:
    Ohio
    Vehicle:
    2009 Prius
    Model:
    Five
    Here's an update. With a fully recharged 12V battery, I replaced the the RH Rear hub and sensor assembly, due to the code saying that is where the fault was located. Inspected the wire before I did it, and it does appear intact and unchewed.

    Tried to reset tonight, and it still shows that fault.

    My other ongoing code says the #2 oxygen sensor is bad. I have replacement in hand, and will update, when I get a chance to install it.

    I read a post about the brake error I have and the owner had to get the ABS module replaced to fix it, after also replacing the sensor. That might be where I am heading. I replaced an ABS Module in a Honda, and bleeding the system was quite a pain in the neck.

    My charger has a mode for this type of battery, by the way.

    Thanks,

    Zapman
     
    #12 Zapman, Sep 18, 2018
  13. Zapman

    Zapman Junior Member

    Joined:
    Sep 15, 2016
    12
    7
    1
    Location:
    Ohio
    Vehicle:
    2009 Prius
    Model:
    Five
    In case anybody is curious, here's an update. Replaced O2 sensor, and discovered old wires had been chewed through!!! Exstustudent was right. Looked at the inside wiring of RH Rear ABS sensor and discovered chewed wire inside the car! Ordered new harness for that area. The break is just before the plug. That's the last code I am dealing with, because the new, now connected O2 sensor error did not come back.
     
    #13 Zapman, Sep 23, 2018
    Raytheeagle and bisco like this.
  14. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,796
    48,995
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    congrats!(y) time for a cat?:cool:
     
    #14 bisco, Sep 23, 2018
  15. Zapman

    Zapman Junior Member

    Joined:
    Sep 15, 2016
    12
    7
    1
    Location:
    Ohio
    Vehicle:
    2009 Prius
    Model:
    Five
    Final Update: wire harness section to rear right wheel replaced. Brake Light off and all other warning indicators off. Success. I broke off one of the hold down bolts replacing the wiring, but I was able to grind off the welded on nut and replace it with a new bolt and regular nut with a lock washer. It feels good when all the lights are gone.
     
    #15 Zapman, Oct 1, 2018
    Raytheeagle and davecook89t like this.
  16. Usle

    Usle Active Member

    Joined:
    Sep 21, 2018
    317
    139
    0
    Location:
    Me
    Vehicle:
    2018 Prius Prime
    Model:
    Plug-in Advanced
    Had a rats nest on the battery of my truck and daily dropping in my Prius, bought some plug in gizmos, 3 for 3$ that electronically, ultrasonically, repel rodents, four years ago, no rodent signs since, you have an infestation, the infestation-ERS have no reason to not intfestate.
     
    #16 Usle, Oct 1, 2018
(You must log in or sign up to post here.)