Testing gen 2 battery with multimeter and don't know how to use it

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by TheNomadicAspie, Nov 15, 2021.

  1. TheNomadicAspie

    TheNomadicAspie New Member

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    I'm pretty sure I'm using my mutimeter wrong, but all the videos I've found don't really explain what setting to use or how to use it. One person said it should be on the "ohm" setting. If I set it to that and touch the red and black together, I do get a brief spike of a reading.

    But when I touch the red side to the positive side of the cells where the metal screws are, and touch the black to either the metal of the battery or to the negative side, the reading still says 0.L.

    Is this right?

    [​IMG]

    Also some of the videos I've watched mention a charger to test for bad cells as well. I didn't realize that when I bought the multimeter and thought that was enough, and since my car is disassembled I'll need to order it on Amazon and test it, then order the replacement cells once I figure out how many I need.

    So I just wanted to ask if that's something I should definitely do as well? Does it matter what type of charger I get?

    My 08 Prius has the problem light and a bunch of check engine light readings. The codes are p0420 (cat efficiency below threshold), c0200 (right front wheel speed sensor signal malfunction, c0205 (left front wheel speed sensor malfunction), c1241 (low battery positive voltage or abnormally high battery positive voltage), c1242 (open circuit in ig2 circuit), and c1300 (malfunction in ecu).

    And could anyone help me figure out why my reading stays at 0.L when I test the cells?
     
  2. bisco

    bisco cookie crumbler

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    why are you testing the hybrid battery, does one of those codes apply?

    i would set it to volts and check the 12 volt battery with the car off, and then again after the headlights have been on for 5 minutes.
     
  3. ChapmanF

    ChapmanF Senior Member

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    Have you written a will?

    There's not one of those codes that has anything to do with the traction battery, raising the question what you are doing in there at all.

    That would be a question even if you knew what you were doing with a multimeter.
     
  4. TheNomadicAspie

    TheNomadicAspie New Member

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    Everyone I've explained the situation to online has said the same thing, and that I should take it to a hybrid mechanic. But when I called a hybrid mechanic to take it in, I was told that if the problem light is on, it's 100% the traction battery.

    Another friend who's a mechanic said the same thing, so I'm not sure what to do.

    I don't want to pay a mechanic to look at it if they say it's the traction battery, because they won't replace the individual cells if so. So I figured I would make sure it wasn't the traction battery before taking it to a mechanic, so I can at least rule that out before paying for a diagnostic, especially since those mechanics say it's the traction battery.
     
  5. ChapmanF

    ChapmanF Senior Member

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    Holy smokes, I get that anybody can hang out a shingle as a "hybrid mechanic", but rarely have I heard of one saying something that flagrantly bogus before.

    You can be 100% sure that it's either the traction battery or one of the couple hundred other things that can light that light. That's why there are trouble codes to read and a repair manual (more info, presumably a "hybrid mechanic" has already heard of it) to look up what they mean.
     
  6. pasadena_commut

    pasadena_commut Active Member

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    Step away from that meter - you don't know what you are doing and are going to blow it up, blow your car up, or blow yourself up.

    There should be a manual for that meter. It will tell you what the various modes are. For most car work you are going to be using only the DC voltage (probably the V with bar over three dots, but verify in manual, and in a range which measures up to say 20V), and resistance (what you have it set to now.) "0L" generally means it is reading below the minimum value supported for that range. For resistance those are typically marked as 10, 100,1000, 10K, 100K, and so forth with the ohm mark (capital Greek omega). Looks like it might be set on yours by pressing the range button. You are unlikely to be making a current measurement, to do that you must put the meter in series with the part of the circuit being tested.

    Now here's the thing, in general measuring DC voltage is pretty safe as long as you don't short anything out with the probe. If you screw up at worst you will get a 12V shock which is very minor. HOWEVER, this is not true for the high voltage leads around the battery. The voltage there can kill you, and if you don't understand already everything written above you have absolutely no business poking around in or near the traction battery.
     
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  7. TheNomadicAspie

    TheNomadicAspie New Member

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    You're completely right and I shouldn't have done it, fortunately I survived but after putting the battery back, the car doesn't accelerate despite turning on, it just goes into neutral.

    So I towed it to the hybrid mechanic with the highest rating on Google and waiting for an update.
     
  8. rjparker

    rjparker Senior Member

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    I am glad you lived. Some don't. Sad to say, but a few on Priuschat and youtube encourage people to tear apart hybrid batteries as if it was common sense we were born with. Even dealer Toyota mechanics have to be specially certified to work on a hybrid battery. Even then they may replace bad parts and cells with new, not used.

    To start you need to have some basics of electrical theory under your belt. Try this guy, particularly pages 13-26. Then read your meter manual.

    https://lost-contact.mit.edu/afs/adrake.org/usr/rkh/Books/books/electronics/Mims.-.Getting.Started.In.Electronics.(1994).pdf
     
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  9. bisco

    bisco cookie crumbler

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    i hope they aren't replacing cells at dealers
     
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  10. SFO

    SFO Senior Member

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    Those codes (DTCs) are all over the place, which OBD2 code scanner are you using?

    Best to use a toyota hybrid compatible OBD2 scanner, or a mini-vci cable and 'techstream' (dealer technician diagnostic software).
    Setting aside the "FUD", and given the local operating environment, you may have a high voltage ground leak (DTC P0AA6, aka P3009).

    If so, and assuming you want to keep this vehicle for any length of time, it's always best to go with a "new" HV battery replacement. Some of the NEW options are; new OEM from the dealer (OTC if possible), new aftermarket NiMH, or a new 'bleeding edge' Lithium pack.
     
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