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2008 with 290k miles - brake, ABS and VSC lights on

Discussion in 'Gen 2 Prius Main Forum' started by crooner, Jan 9, 2024.

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  1. crooner

    crooner Member

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    Ok, so I looked at older threads and came up with this. Some of the text came from ChapmanF responding to another poster.

    Brake symbol (ECB)

    36 = "Hey, there's also an ABS code."

    41 = Full trouble code C1241

    C1241 pertains to low voltage arriving at the brake actuator/ECU. It doesn't have to mean the auxiliary battery (you said that's fairly new); if it isn't that, it's probably a deteriorated wiring connection somewhere in the wiring path from there to the brake actuator. There are several different INF codes that pin down the situation further, but you can't get those with light blinks; that takes a scan tool.

    ABS

    32 = C0205/32 - Left front wheel speed sensor signal malfunction.

    36 = C1236 = Left front wheel speed sensor, waveform noisy for five seconds or more at 12 MPH or above, or noisy in sync with wheel revolutions above 6 MPH for 15 seconds or more.

    42 = "Hey, there's also an ECB code."


    VSC

    43 = "Hey, there's also an ABS code."

    45 = "Hey, there's also an ECB code."

    So it appears there is a bad ABS/speed sensor on the left front wheel. Maybe the bearings are bad too.
    The low voltage going to the actuator code is interesting. Maybe the auxiliary battery is going bad. Interesting this would all happen at the same time. The fact the lights tend to go on when going through bumps could mean the wiring is flakey somewhere.

    This is a California car, and I'm in the desert, so no rust issues.

    The good news is that the actuator appears to be ok. Thank God!
     
    #21 crooner, Jan 23, 2024
    Brian1954 and mr_guy_mann like this.
  2. Frontporch

    Frontporch Member

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    It sounds to me like your abs sensor has gone bad. could be as simple as a wire got damaged by some road debris. I have also damaged the sensor end myself by forgetting to torque the axle nut and move the car out of the driveway. In general once installed the sensor should be protected, but the wire is always at risk.
    If you had a bad bearing you should be able to diagnose that with your ears. I think I may have a bad bearing in its early stages, but I am waiting for it to get worse.
     
    #22 Frontporch, Feb 5, 2024
    crooner likes this.
  3. crooner

    crooner Member

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    Yes, I will see if I can have that checked. I can't hear any bearing noise. By the way , I replaced my tires the other day and the light hasn't come back on. Fingers crossed!
     
    #23 crooner, Feb 5, 2024
  4. Frontporch

    Frontporch Member

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    It appears that I didn't read your response carefully enough. a bad ABS sensor wouldn't fix itself so you are probably on the right track with the aux battery or a connection or ground somewhere. No need to check anything ABS related until you get some indication on the dash that things aren't working.

    I have been lucky with the aux battery, never really having a problem, but I have seen here where a new battery fixes lots of strange behaviors. There are lots of posts here with suggested voltages (for different situations like resting, ready..) that point to battery health. I would probably measure those for a better idea.

    Just to clarify, what lights are coming on when you go over bumps. The ABS, VSC...? The prius is notorious for flashing the traction control light when braking and encountering rough roads. Nothing to do there but give yourself a little more room when following another car.
     
    #24 Frontporch, Feb 5, 2024
  5. crooner

    crooner Member

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    It's the ECB, ABS and VSC lights only. I've seen the traction light come on briefly too, but it's not that one.

    My aux battery was installed in 2021, dealer bought Toyota battery. It replaced an Optima the previous owner installed. I was going to get another Optima but folks here in Prius chat recommended the dealer OEM battery...
     
    #25 crooner, Feb 5, 2024
  6. Frontporch

    Frontporch Member

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    Sorry to make you repeat yourself. I didn't go back in the thread before posting.

    If there is some noise on the speed sensor maybe somebody has some thoughts as to how this can happen. I believe the sensor itself is a magnet, but I have never seen junk collected on the end by the tone ring. Damage to the wiring in the wheel well is not uncommon. Maybe you have a damaged/bare wire that contacts ground when you go over bumps? or maybe wires contacting each other. Even as the wires leave the area in the wheel well and seem protected, I have owned cars where rodents have moved in and chewed all of the insulation off wires leaving bare copper. You might try to follow that abs sensor from wheel hub to harness connector as far as you can to check for anything that looks suspicious.
     
    #26 Frontporch, Feb 6, 2024
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