Low Voltage to Scan Tool

Discussion in 'Gen 2 Prius Main Forum' started by ShadeTreeMech, Mar 5, 2023.

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  1. ShadeTreeMech

    ShadeTreeMech New Member

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    Hi All – I just completed replacement of ABS Actuator Module for my 04 (bit of a hassle but doable). I did the necessary full brake bleed using a Snap-On Solus Legend. For whatever reason the tool would not clear the ABS codes, so I used the jump OBD 4/13 jump method and eventually got them cleared. The last thing I need to do is the solenoid relearn offset, but now my scanner is indicating low voltage from vehicle and won’t read anything. I’m not great with the electrical side of things, so I’m hoping someone can steer me in the right direction. Is it possible the jump (I used electrical wire with ends stripped) causes an arc and carbon scoring on OBD or did I fry a fuse? I’m not even sure where to begin as my electrical knowledge is poor. Much thanks for any help as I shed all my tears over the actuator itself☹.
     
    #1 ShadeTreeMech, Mar 5, 2023
  2. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    It's your 12v battery becoming discharged- possibly door left open or your diagnostic session just ran long enough that the car's 12v battery has been pulled low from powering the scanner.

    The ABS pump is going to need a healthy supply of 12v power too, so get it charged up before you try that learning procedure.

    If the car can make READY that will recharge the battery, or hook up a trickle charger to top it up & hold it over when doing extended sessions.
     
    #2 Leadfoot J. McCoalroller, Mar 5, 2023
  3. ShadeTreeMech

    ShadeTreeMech New Member

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    Thank you
    I had put a charger on 12v shortly after posting this and just confirmed it has full charge and scanner is still reading low/no voltage. Engine starts freely and all systems seem fully powered, so I'm wondering if the "jump" of pins 4 and 13 to clear ABS codes blew a fuse or such. Any ideas? Thanks for your thoughts in any case - really appreciated.
     
    #3 ShadeTreeMech, Mar 5, 2023
  4. mr_guy_mann

    mr_guy_mann Senior Member

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    #4 mr_guy_mann, Mar 5, 2023
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  5. ShadeTreeMech

    ShadeTreeMech New Member

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    Thank you Mr_Guy!! Fuse 8 was melted likely from my jump, but I replaced and scan tool was able connect immediately. I'm so appreciative for the help - I haven't been this happy since my mother-in-law left after the holidays:) Thanks again!
     
    #5 ShadeTreeMech, Mar 5, 2023
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  6. ShadeTreeMech

    ShadeTreeMech New Member

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    Also, I forgot to ask how you knew which fuse was the culprit. I don't need to be a wizard like you, but I'd like to get better at this.
     
    #6 ShadeTreeMech, Mar 6, 2023
  7. mr_guy_mann

    mr_guy_mann Senior Member

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    I'm sure it's SOMEWHERE in the factory wiring diagrams, but Toyota can make it difficult at times. (I looked but only found "partial" diagrams for the OBD2 connector- none seemed to show the power and ground pins).

    Instead I looked on the web for the fusebox diagram. It lists what each fuse protects. Same info that's in the owner's manual.

    Part of everything is experience- I know what pins at the connector have data lines and that it also has battery power (pin 16) and two grounds (pins 4 &5). USUALLY 16 has a dedicated fuse, sometimes the engineers (bean counters) tap it into a power outlet circuit.

    Once you know that something specific exists, you can look for it until it's found.

    Posted via the PriusChat mobile app.
     
    #7 mr_guy_mann, Mar 6, 2023
    Last edited: Mar 6, 2023
  8. ChapmanF

    ChapmanF Senior Member

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    Different system diagrams show pins at the DLC3 connector relevant to them. Both the TOYOTA Hybrid System and the Engine Control section show power and ground pins.

    obd.png
     
    #8 ChapmanF, Mar 6, 2023
  9. mr_guy_mann

    mr_guy_mann Senior Member

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    True enough. Ya gotta know where to look. Multiplex communication (and other diagrams) have partial schematics. Would have nice if they had one labeled - "DLC connector".

    Posted via the PriusChat mobile app.
     
    #9 mr_guy_mann, Mar 7, 2023
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