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Yellow break indicator light - DTC C1377

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jobbin, Jan 24, 2017.

  1. jobbin

    jobbin New Member

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    Since like a week back I have had problems with the yellow break indicator (looks kinda like this ( ! ) ) lighting up about 5 seconds after starting the car. First couple of times it dissappeared after restarting the car, but now it wont go away.

    I had the 12v battery changed like 4-5 weeks back.
    My local shop scanned the car with a VCI and it showed "C1377 - Capacitor, malfunction".

    After some googling I found that this points to the PBCU (Power Break Control Unit) that sits beside the 12v battery.
    I've unplugged and replugged all cables to the 12v battery (including from the PBCU) without luck. I have also checked the 3 ABS fuses with a multimeter and they are all fine.


    Its a Gen2 prius from 2004.


    Any ideas?
     
  2. dolj

    dolj Senior Member

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    Perhaps the capacitor(s) in the PBCU have developed a problem (leaking, for instance?) and the PCBU is now malfunctioning?
     
  3. jobbin

    jobbin New Member

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    Yeah I guess that could be the case. Is there anything else that I can try before replacing it?
    If I am going to replace it, can I do it myself? It looks easy (just one cable), but is there something else that needs to be done (reset/reflash)?
     
  4. bisco

    bisco cookie crumbler

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    how many miles on her? i would test the 12v to be sure it's charged.
     
  5. dolj

    dolj Senior Member

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    You could subscribe to techinfo.toyota.com where for $15 for 2 business days access you can access the Service Bulletins, Repair Manuals, Wiring Diagrams, Technical Training and Other Technical Information which would include the diagnostic tree for the C1377 DTC to see if there are any tests you can do.

    I'm fairly certain that, if you opted to just replace it, it is just a straight forward remove and replace. There is no requirement for a reset/reflash.
     
  6. jobbin

    jobbin New Member

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    About ~150k miles. The 12v battery was swapped just 5 weeks ago. No other signs of a bad battery, everything works as expected.

    Thanks for the tip! If no one else have any ideas i'll take a look!
    Also nice to hear that it should be easy to replace it.
     
  7. jobbin

    jobbin New Member

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    I bought a used PBCU for ~70$ and it solved the problem! Indicator light went out - fingers crossed that they keep doing that :)

    Thanks everyone!
     
  8. Varun Hknz

    Varun Hknz Junior Member

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    Hey mate, I started getting similar errors after getting a general service done.
    C1241: Low battery positive voltage or abnormally high battery positive voltage
    C1249: Open circuit in stop light switch circuit
    C1377: Capacitor Malfunction
    I was ignoring these lights for the last 4 weeks, as the car was running fine.

    The warning lights along with the red triangle temporarily disappeared last week, after replacing 12V battery, however they came back after restarting the 3rd for the third time. I inspected the ABS fuses this morning in day light. They don't seem to be fried or anything.
    PS. I don't have an amp/volt meter.

    MY QUESTION: Did replacing the PBCU solve your problem completely or have these lights started coming back on again?