Help with lights coming on.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by JoeJack1967, Feb 19, 2020.

  1. JoeJack1967

    JoeJack1967 New Member

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    I was accelerating to 70 mph on the interstate the other day when the brake light, emergency Brake light and ABS light all came on. Traction Control light flashed four times and went out. Using the Prius chat forum to trouble shoot I have replaced my 12V Battery (increased my MPG) and my Noisy Inverter Coolant pump. The lights went out but came back when I was accelerating on the Interstate. Checking the Voltages with the Diagnostic Menu It seems that the 12V drops to 11.8V when under load for more than 2 to 3 min. Battery Voltage is good with no load and 14.2 with engine running. I pulled all my ABS fuses and the battery stayed above 12V under load. Is there anyway to trouble shoot the ABS? Has anyone else had this problem?
     
  2. JoeJack1967

    JoeJack1967 New Member

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  3. valde3

    valde3 Senior Member

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    You just need to get the fault codes read with a scanner that can talk to all control modules (not just engine). If you want to do it yourself Techstream is the best and Mini-VCI is cheap way to get it but requires a laptop.
     
  4. dolj

    dolj Senior Member

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    11.8 V is nothing about which to worry. As Valde said, You just need to get the fault codes read with a scanner that can talk to all control modules. Once you have read all code, you will have a better idea of where to focus your efforts.
     
  5. JoeJack1967

    JoeJack1967 New Member

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    Lights went out today while driving home from work (40 mile trip each way) . It accelerated to 70mph without any problem. About 5 mi from home they came on again. Took a quick trip to the store and the traction control lights flashed 4 times 4 consecutive times before the lights came on again. I disabled the traction control and the lights went out. will it hurt the car to drive it with Traction Control disabled?
     
  6. valde3

    valde3 Senior Member

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    Traction control is turned off by turning the car into maintenance mode it's not really designed to be driven in that. Fault lights not being on in that might just be because of that so there really isn't a reason to drive in maintenance mode just to keep the fault light off. Theoretically car could be damaged if driving in maintenance mode also.

    Just get the codes read.
     
  7. ChapmanF

    ChapmanF Senior Member

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    The reason the lights come on is to tell you that the car's computers have logged trouble codes that will tell you about some issue with the car that needs attention. Without the codes read, the issue is still there, we don't know what it is, and we can't judge what risk you're taking by ignoring it.
     
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