Brake Actuator or Skid Control?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by dandlwelder, Oct 25, 2015.

  1. dandlwelder

    dandlwelder Junior Member

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    About a month ago, I got the dreaded triangle, brake and VSC light. When I got my OBD on, it said C1253, C1256, C1300 and C1313. It went away and then happened again, but when I looked for codes, it said no faults detected. Then I keep the OBD on while I drove, and got a C1310.

    So is it two problems, or really just the brake pump actuator or skid control ECU?

    If it is the actuator, how can you get the right resistor value to match the pump, or does it really not matter?

    I plan on working on it myself, as I have lots of experiance working on cars. Planning to get the VCI software to release the brake pressure.
     
    #1 dandlwelder, Oct 25, 2015
  2. ChapmanF

    ChapmanF Senior Member

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    If you could add to your post a little of what the service manual says about the codes you read, I'd be more confident about helping to diagnose it. It's about $15 for downloading the manuals at techinfo.toyota.com so I hope you'll understand if I don't download your manual myself for the purpose of answering your question ... but on your end it would be $15 very well spent and will be useful to you as long as you own the car. Especially if you have lots of experience and plan to do lots of your own work.

    The codes from my year might not all be the same, so I'd rather not guess based on those.

    Cheers,
    -Chap
     
    #2 ChapmanF, Oct 25, 2015
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I would start by first making sure that the 12V battery is in excellent condition. A new, fully-charged battery will measure ~13.0V out of the box. What voltage will your battery deliver when the car is IG-OFF and it has been resting overnight, prior to the first start of the day? If less than 12.6V, it is getting marginal and should be fully-charged at minimum; consider replacing it if more than four years old.

    If the battery is good, then I suggest checking ABS #2 relay. Find and remove the relay. Apply 12VDC across the relay coil terminals, and measure resistance across the switched terminals using a digital multimeter. If the reading is > 0.5 ohm (after accounting for resistance of the meter leads) then replace the relay.

    If the relay is good, then the fault codes do point to both a failed actuator and a failed skid control ECU. However, let's see what happens after you get Mini VCI to confirm the DTC which continue to be logged.

    When you get to the point where you decide to replace parts, I would start with the ECU as that may take care of all of the issues. That ECU is logging the DTC you reported, and a failed unit may log spurious codes.

    I do not think it is necessary to worry about the resistor if you decide it is necessary to replace the brake actuator. You'll need access to the factory repair manual info if you get to the point where you are replacing the brake actuator and probably would benefit from earlier access.
     
    #3 Patrick Wong, Oct 25, 2015
  4. dandlwelder

    dandlwelder Junior Member

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    1253 Hydraulic Booster Pump Motor relay
    1256 Actuater Low Pressure Malfunction
    1300 Engine Control Unit
    1313 Open Circuit in Main Relay 2
    1310 Malfunction in HV system (skid control )
     
    #4 dandlwelder, Oct 25, 2015
  5. dandlwelder

    dandlwelder Junior Member

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    New Odyssey battery a year ago, no problems starting or having the car's accessories run on the battery alone. But will test the voltage. ABS relay #2 will be checked.
    As far as the service manual, having a tough time at techinfo toyota finding a link. Any suggestions? Do I need to subscribe before seeing the service manual links? see the other manuals, owners, disassembly, glass breakage etc from the TIS section.
     
    #5 dandlwelder, Oct 25, 2015
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, you need to subscribe to TIS to access the repair manual info.
     
    #6 Patrick Wong, Oct 25, 2015
  7. dandlwelder

    dandlwelder Junior Member

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    OK, Used the VCI just got low voltage and abnormal voltage change on each wheel, (C1271-1278) then a C1281 Master cylinder pressure sensor output signal is fault and C1346 Stroke sensor zero point learning abnormality. What would make the voltage at ABS sensors be low and change abnormally, bad relay?
     
    #7 dandlwelder, Oct 27, 2015
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Since all of those DTC were logged, I would think the skid control ECU has failed. That is more likely than the possibility that all four wheel speed sensors have failed, not to mention the master cylinder pressure sensor.
     
    #8 Patrick Wong, Oct 27, 2015
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