3 Brake warning lights come on - no codes stored?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Confrad in VA, Feb 25, 2017.

  1. ChapmanF

    ChapmanF Senior Member

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    Or stick a jumper wire between TC and CG ....
     
  2. Confrad in VA

    Confrad in VA Junior Member

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    Ignore all of the other lights in the photo. I took this photo upon start when ALL the lights come on, then turn off after about 3 seconds. I was just trying to show which 3 lights are the ones that stay on occasionally. Never an accident, and no other lights are on after the car starts!
     
  3. Confrad in VA

    Confrad in VA Junior Member

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    Sorry to say, but I'm glad I'm not the only experiencing this. I see it's your 2006 also. Mine happens with about the same frequency. Never can tell when they are going to be on. Do you notice any change in braking when this happens?
     
  4. Shaun_Collins

    Shaun_Collins Junior Member

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    Nope. Never see the problen on the wifes '04. My friend from work never reports the problem on his '07 so must be particular to this year model. I am pretty sure the antilock module assembly is year specific as replacing these you must match your part number according to most authorities like Harrison interchange and ebays used parts built in effectivity interchange and their salvage sellers notes. I do upon ocassion temporarily when using techstream to watch some weak module or weed out location of block of module pair that is intermittiently mostly when warmer out kicking out a APO80 or whatever exact code causes the dreaded red triangle if death that translates to Hybrid pack replacement that is really just a 1 25Vdc difference between any blocks) see a data lack of communication between computers that never sets a pending or hard code. This might be the root cause but simple educated guessing here have zero proof.
     
    #24 Shaun_Collins, Feb 26, 2017
    Last edited: Feb 26, 2017
  5. Confrad in VA

    Confrad in VA Junior Member

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    I see on other threads that members definitely DO NOT recommend shorting these pins and using the "blink" method:

    - "As a friendly little PriusChat reminder, based on the schematics I posted ....
    Never, ever EVER touch pins 4 & 13 on the DLC/OBD port.
    Ever"
    - "pin 13 is TC, which is used for the SRS diagnostic. There is a special service tool #09843-18040 that you use to activate the SRS diagnostic.
    Note: I would never, ever recommend just using a wire. If you happen to touch the wrong pins, you still risk catastrophic damage"
    - "The service manual *strongly* cautions about using the "blink" method. For example, a SST is required which is "goof proof." Just using a wire, they warn that shorting the wrong pins can cause "malfunction and damage." I bet!"

    These are enough warnings to steer me away from trying this.
     
  6. Shaun_Collins

    Shaun_Collins Junior Member

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    Have done those reset methods. Both as in paperclip one and Techstream but problem of 3 yellow lights just reoccurs at random and is not a relevant fix as it goes away on its own quick enough to not require resetting.

    Sent via my LG V20 on Tapatalk
     
  7. Confrad in VA

    Confrad in VA Junior Member

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    There is a TSB that might be related. I found this on a search:
    Customer:
    Is TSB-0174-12 related to this issue?
    AMD :
    Typically the issue we have with the lights is an electrical issue, but the brakes themselves would be functional
    AMD :
    Yes that is the TSB I talked about with the update.
    Customer:
    TOYOTA: INSTRUMENT PANEL ILLUMINATES WITH MALFUNCTION OF ABS/VSC, MIL ON AND BRAKE WARNING LIGHTS, RESULTING IN OVERLY SENSITIVE MONITORING LOGIC WITHOUT ANY ABS/VSC SYSTEM ISSUE. MODELS 2007-2011 CAMRY; 2004-2009 PRIUS. ( NHTSA ITEM NUMBER - 10048160 )
    AMD :
    there's an update to the computer logic which will solve this issue.
    Customer:
    DOes it count as a recall item?
    AMD :
    Not really, because even if that malfunction would occur the brakes would still work fine, just not to their full potential.

    Can't really tell from this conversation if it is the exact same problem - doing more searches on this TSB now.
     
  8. Confrad in VA

    Confrad in VA Junior Member

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    I found these Toyota TSB's, but they both refer to a code being present, both of our OBD monitors (mine and Shaun_Collins) show no codes present or stored.
    static.nhtsa.gov/odi/tsbs/2014/SB-10048160-2163 (DOT)pdf
    static.nhtsa.gov/odi/tsbs/2014/SB-10048160-3140(DOT)pdf
     
  9. ChapmanF

    ChapmanF Senior Member

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    Seems a little bit overwrought (and when I look for those quotes, they seem to have come all from one thread, where one poster said a bunch of scary stuff).

    One can find pictures of the vaunted special service tool ... it's a wire (with crimped-on pokey ends).

    [​IMG]

    It certainly is good advice to "count twice, insert once" to make absolutely sure you know which pins 4 and 13 are. If you anticipate checking codes often, it can be easier if you build a thing like I did:

    abtstca.png

    The TS and TC switches are both center off, up for ON, down for momentary ON, because the manual has various procedures where you make things happen by not just tying the signal to ground but by pulsing it some number of times, which is clumsy to do with a wire. AB (only for Gen 1, later Prius gens don't have an AB circuit) is only a pushbutton, because the only procedures that use it in Gen 1 involve pulsing it some number of times.

    But the basic "blink me out the diagnostic codes" command is just to connect TC to ground, period. Nothing fancy. And it does what it says on the tin.

    I did just recently learn that TS is a different pin number for Gen 2 and later than for Gen 1, which is why my little box now has the newly added slide switch at the bottom to select which pin the TS switch goes to.

    This rides around in my glove box all the time, unlike a laptop with Techstream, which can pull a lot more information, but is just too bulky to have live in the car.

    -Chap
     
  10. Confrad in VA

    Confrad in VA Junior Member

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    I have Gen 2 so I assume it's still 3 & 14?
    I'll give it a try in the next day or 2, depending on when the lights come on again.
    Just to review the procedure:
    - Turn car on
    - if the warning lights appear: jumper 3 to 14 while looking at the lights and count any flashes.
    - any flashes should look like this for example?
    flash flash flash pause flash flash pause flash flash flash?

    Question: will this be a one time flashing or will it repeat as long as the pins are jumpered. Should I have someone watching as I jumper them to catch any flashes?
     
  11. ChapmanF

    ChapmanF Senior Member

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    Nope nope nope nope nope ... 4 and 13.

    CG has always and forever been pin 4 (it's defined in the OBD-II standard). TC hasn't budged from pin 13.

    It's the TS signal that changed pins between Gen 1 and Gen 2. That doesn't concern you, unless you later need one of the procedures that involves using TS.

    For blinking out codes, TC (13) and CG (4) are all you need.

    [​IMG]

    Be sure you pay attention to which way the DLC3 connector is mounted ... it may or may not be wide-side-down like that picture.

    Codes will continue blinking as long as you have the pins jumpered. You know you've seen the whole list when it comes back around to one you already wrote down.

    -Chap
     
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  12. Confrad in VA

    Confrad in VA Junior Member

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    My bad - my dyslexia kicking in :(
    (i'll definitely have to count twice)
     
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  13. eman08

    eman08 Active Member

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    Sounds like a computer control module going bad or sensors.

    Posted via the PriusChat mobile app.
     
  14. ChapmanF

    ChapmanF Senior Member

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    A couple reports upthread were of lights with no codes to read. If there are really no codes, generally sensors would be ruled out (a sensor problem would be reported with the codes telling you what sensor problem you have).

    ECU going bad would be a possible explanation for weird lights with no readable codes. The only thing is, by experience, a "lights but no codes" post on PriusChat usually means "lights and the code reader I was using did not retrieve codes", and ECUs, being solid state electronics, really don't all that often go bad.

    That's why, before jumping to any conclusion like "module going bad", I'd suggest the simple, no-scantool-required built-in blink-out-the-codes test.

    -Chap
     
  15. Douglas88

    Douglas88 New Member

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    I have the same issue on my 95. Was this issue ever resolved? Thanks
     
  16. Mendel Leisk

    Mendel Leisk Titanic Social Director

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    Slipped a decade? :whistle:

    Welcome!
     
  17. ChapmanF

    ChapmanF Senior Member

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    Well, let's get started, first by figuring out if it's likely the same issue or not. As you tagged on to a "lights but no codes" thread, I assume you've already tried to pull codes with an inadequate reader and it didn't show you any. Have you pulled them yet with either Techstream or the TC-to-CG jumper wire, and what were they?

    -Chap
     
  18. ChapmanF

    ChapmanF Senior Member

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    Though I've used this box without issues for years to do the non-Techstream "jumper TS or TC to CG" kinds of procedures, the last couple times I've gone to use it, it the car's Master Warning Light has come on immediately, along with flashing PRNDB segments and a message about the parking mechanism. Unplugged again, cycling the power button leaves the MWL on and the "CHECK HYBRID SYSTEM" message. Yuck. Fired up Techstream, saw a bunch of comm errors logged, and cleared them. Warnings go away.

    Plugged my box on again, and woop! back with the MWL. Simply from having the box plugged in, not using the TC or TS switch or the AB button. I've had the box apart, looked for shorts in my wiring, ohmed things out, didn't find a problem.

    At least I figured out the comm error warnings will go away by themselves after a few drive cycles, so I don't have to keep lugging out the laptop and Techstream to clear them.

    The ScanGauge that I have plugged in all the time never has that effect. And this box used to do just what I built it to do; it never caused comm errors just by being plugged in before.

    Only difference I see at the moment is that the ScanGauge cable connector has gold-plated pins. I built this box on a cheapie J1962 connector with unplated pins. And I've had it about ten years now, riding around in the glove box. I wonder if the pins are just that bad now.

    I have another cable sitting around with gold-plated pins, and I can plug that one into the car and it doesn't trigger comm errors. Guess maybe I'll rebuild the TC/TS/AB box using that ....

    -Chap
     
  19. ChapmanF

    ChapmanF Senior Member

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    Success ... the resurrected Ts/Tc twiddler built on a J1962 plug with gold-plated contacts is rock-solid, I can plug it in or out with the car off, on, or ready, no glitches, no comm errors, the twiddle switches do just what they're supposed to, nothing weird happens.

    twiddler.jpg

    My old one with the unplated contacts worked equally well when I first built it, but had gotten to the point where it would cause comm error reports from several different ECUs, just by being plugged in at all.

    -Chap
     
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