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Brake System Dummy Lights: ABS, Traction Control

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by well.rested, Jun 20, 2016.

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  1. well.rested

    well.rested Junior Member

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    I recently bought my first Prius, a 2014 Prius C. I love the little thing, hasn't given me any trouble, bought it w. 50k miles on the odo. Today, while driving, nothing unusual happening, my dummy lights come on, the ABS brake light, the (!) Brake System light, and the Slip Indicator light. The car seemed to drive OK, though the brakes felt a little funny, like maybe the regenerative system wasn't kicking in ahead of the actual brakes. I was very close to home, so I pulled in and shut the car off... turned it back on, no lights, no problems. After leaving the car sit for an hour, I took a ~15 mi. drive with no problems... until I get near my house, lights come on again, definitely no regenerative braking. The charge bar still indicates charging when I brake, but the "slow-down" stage-1 regenerative is no longer there, just the regular brakes. Lights once again stayed off after restart. Anyone else have a similar experience? Is this a warning sign of problems down the road (as it were)? I have full-coverage warranty up to 100k miles, but don't want to spend the $200 deductible if I don't have to...

    Thanks for any advice,

    ~Adam
     
    #1 well.rested, Jun 20, 2016
  2. bisco

    bisco cookie crumbler

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    you need to have the trouble codes read. what is the outside temp?
     
    #2 bisco, Jun 20, 2016
  3. well.rested

    well.rested Junior Member

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    Is there any reason to expect the actual brakes to go out? This is my main concern...

    Will a standard ODB reader give me codes on a hybrid? Temps are warm, have been in the mid-90s, but were cooler today. I'm mostly just concerned about the actual brakes going out, but I think... it was an adjustment, driving with the regen system, and now that it's not there it's freaking me out a little. I'll look into getting diagnostic codes off the car's internal system and checking the 12v with my multimeter... thank you for the quick response. A little more info, after driving today... the regen system seems to be working inconsistently, I drove from my office to grab lunch and the warning lights came on almost immediately, later in the day the same thing, after a pit stop on the way home (perhaps 5 mi. from my office), the lights were off and stayed that way all the way home, regen working fine.


    ~Adam
     
    #3 well.rested, Jun 21, 2016
  4. ChapmanF

    ChapmanF Senior Member

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    You could be overthinking this ...

    Those lights are there to be warnings, so, yes.

    Your next questions are probably "how severe?" and "how far down the road?" and those questions require the trouble codes from the brake controller. The codes are what tell you what problem is being detected, of which there are too many possibilities to spend time guessing at. From the lights alone, all you know is that there's a problem and you need the codes read.

    All your various observations about whether it feels funny, when the regen feels like it kicks in, etc., are not bad things to notice, and might even turn out to be helpful in interpreting the trouble codes ... but the time that passes doing that instead of getting the codes read is passing without solving the problem.

    For reading the brake codes, there are some scan tools that will work (especially Toyota Techstream with a J2534 adapter like the Mini VCI) but most vanilla OBD readers will not. At least the first 3 Prius generations all have an alternate way of reading the brake codes with a jumper wire and blinking lights. I don't know about the c but I would not be surprised if it has that alternative too. The repair manual will say if it does.

    I wouldn't expect a dealer to charge any more than the minimum billable labor time to plug in their scantool and get you the codes. That might be the simplest and fastest approach, if you don't have a usable tool already and you'd just like to know what's up with the brakes.

    -Chap
     
    #4 ChapmanF, Jun 21, 2016
  5. Sean Nelson

    Sean Nelson Active Member

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    I gotta ask the obvious question just to rule it out - is there any chance that the wheels actually slipped on some sort of slick surface as you braked? If so, the antilock braking system would kick in and produce exactly the symptoms you describe.

    I've seen this happen on my Prius C in snowy conditions, but anything that's slick could cause it, or even in good conditions if you brake aggressively enough to lock up the wheels.
     
    #5 Sean Nelson, Jul 2, 2016
  6. Sonic_TH

    Sonic_TH Active Member

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    Did you found what was the cause of the problem? and did you ended fixing it?
     
    #6 Sonic_TH, Dec 4, 2020
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