Clicking from HV batter area when attempting "ready"

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by labumm, Nov 9, 2019.

  1. labumm

    labumm Junior Member

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    I have a 2004 Prius ~142k with original HV battery. It hasn't run for 8-10 months. The aux battery (new Optima AGM Oct 2018) has been out during that time and on a charger. The combo meter replaced Jul 2018.

    Today I put the aux battery in. It seems t get to ig-on OK, but he gas gauge was on E (one bar flashing). So I added 5 gal, gas gauge registers ~1/3 tank. But it won't go into ready. when i try to do that, I hear a clicking in the battery area. More specifically, there are 2-3 clicks while the "ready" light flickers in the combo meter each time I try toe start the car. (I have everything out of the trunk to get the spare, so it is easy to localize the sound.)

    I was worried the NiMH would be dead. The screen shows it is mostly charged and in the blue, but that could just be in memory from the last time the car was running (?).

    Any troubleshooting suggestions would be appreciated.
     
    #1 labumm, Nov 9, 2019
    Last edited: Nov 9, 2019
  2. ChapmanF

    ChapmanF Senior Member

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    The clicking is the only part of this picture that is normal. :)

    There are three relays back there that keep the battery isolated from the rest of the car when the car's off: one on each side of the circuit, and a 'precharge' one with a resistor. Every time the car goes ready, it's a sequence of (two clicks together, sounding like one)--(another click)--(another click). Every Prius makes those clicks every time, which we normally don't pay any attention to because the car is working (and they're harder to hear when the trunk's not emptied out).

    On power down, of course two more clicks together (which can just sound like one at times).

    Sounds like your car is going ahead and powering up (clickity click) and then thinking "hmm, don't think so" and powering down again (kaclick).

    The troubleshooting suggestion is to relax about the clicks and focus more on reading the trouble codes that will tell you why the car is saying "hmm, don't think so."
     
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  3. bisco

    bisco cookie crumbler

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    i would check the 12v health
     
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  4. bisco

    bisco cookie crumbler

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    and all the connexions
     
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  5. labumm

    labumm Junior Member

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    I connected my scan tool. the code is P0303, which seems to be a generic power train error. The "control module voltage" (SAE 0x42) is 11.6 V, I assume that's the 12V buss voltage, which is pretty low. The voltage on the posts is 12.05 V, so I'll charge it again to see if I can bring it back to life.

    I was a but surprised. Usually I have noticed the dome lights dim, etc. With the scan tool you can see the voltage droop when the head lights are turned on and so forth.

    I've had more trouble with the aux batteries than anything else. It's nuts.
     
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  6. bisco

    bisco cookie crumbler

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    it is the achilles heal of prius
     
  7. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    Did you mess with the orange disconnect plug on the HV battery? This sounds like an improperly installed plug.

    It's ( the 12 volt battery ) really not. I've personally worked on hundreds of Prius and just don't see the problems you assign to the 12 volt battery.
     
  8. bisco

    bisco cookie crumbler

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    not just me, many here over many years
     
  9. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    No,
    You promote the useless and wasteful replacement of 12 volt batteries and ignore that it rarely fixes anything.

    Again,
    I have spent close to a decade of hands on work on HUNDREDS of Prius. I just don't see 12 volt batteries being the cause of all the problems you assign to them.
     
  10. bisco

    bisco cookie crumbler

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  11. bisco

    bisco cookie crumbler

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    i don't promote replacing them unless they are bad. i promote testing them. see post #3
     
  12. dolj

    dolj Senior Member

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    Just to clarify, P0303 is not a generic powertrain error, it is a specific powertrain error, namely Cylinder 3 Misfire Detected.

    Here is some info about the misfire information:

    DTC Cookie-cutter one-liner
    1 P0300 Random / Multiple Cylinder Misfire Detected
    2 P0301 Cylinder 1 Misfire Detected
    3 P0302 Cylinder 2 Misfire Detected
    4 P0303 Cylinder 3 Misfire Detected
    5 P0304 Cylinder 4 Misfire Detected

    DESCRIPTION

    When a misfire occurs in the engine, hydrocarbons (HC) enter the exhaust gas in high concentrations. If this HC concentration is high enough, there could be an increase in exhaust emissions levels. High concentrations of HC can also cause the temperature of the catalyst to increase, possibly damaging the catalyst. To prevent this increase in emissions and limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the catalyst reaches a point of thermal degradation, the ECM will blink the MIL. For monitoring misfire, the ECM uses both the camshaft position sensor and the crankshaft position sensor. The camshaft position sensor is used to identify misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. The misfire counter increments when crankshaft rotation speed variations exceed threshold values.

    If the misfiring rate exceeds the threshold value and could cause emissions deterioration, the ECM illuminates the MIL.

    DTC No. DTC Detection Condition Trouble Area
    1 P0300 Misfiring of random cylinders is detected during any particular 200 or 1000 revolutions 1 trip detection logic: MIL blinks 2 trip detection logic: MIL illuminates
    • Open or short in engine wire harness
    • Connector connection
    • Vacuum hose connection
    • Ignition system
    • Injector
    • Fuel pressure
    • Mass air flow meter
    • Engine coolant temperature sensor
    • Compression pressure
    • Valve clearance
    • Valve timing
    • PCV hose connection
    • PCV hose
    • ECM
    2
    • P0301
    • P0302
    • P0303
    • P0304
    • "For any particular 200 revolutions of engine; misfiring is detected which can cause catalyst overheating (This causes MIL to blink)"
    • For any particular 1000 revolutions of engine; misfiring is detected which causes a deterioration in emissions (2 trip detection logic
    • Open or short in engine wire harness
    • Connector connection
    • Vacuum hose connection
    • Ignition system
    • Injector
    • Fuel pressure
    • Mass air flow meter
    • Engine coolant temperature sensor
    • Compression pressure
    • Valve clearance
    • Valve timing
    • PCV hose connection
    • PCV hose
    • ECM

    NOTICE:

    When several codes for a misfiring cylinder are recorded repeatedly but no random misfire code is recorded, it indicates that the misfires have been detected and recorded at different times.



    I hope this helps.


    If the evidence does not support the testing or replacing, then it just becomes a distraction. Some good judgement is called for.
     
  13. Adolfo Gaona

    Adolfo Gaona New Member

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    If the Vehicle was running fine before it sat for 8 to 10 Months then your hybrid battery is below nominal voltage that is 201.6 Volts. The Battery Displaying blue bars isn't accurate because that was the reading before it sat. Once the car turns on it will adjust. My Recommendation to you is to remove it and check the voltages of each cell and get them above 7.2. Don't buy a battery, you might get some life out your old one still.
    .
     
  14. dolj

    dolj Senior Member

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    Even though you are correct in saying 201.6 V is the nominal voltage, the HV battery needs to be at 215 V or more to start the car.
     
  15. ChapmanF

    ChapmanF Senior Member

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    What scan tool did you use? I ask because the only code you have posted is an engine code for a misfire, and no codes from the hybrid computer that would tell you why it prefers not to go READY. That is typical of using a generic scan tool that knows there's an engine computer and doesn't know there's a hybrid computer.

    I wouldn't obsess about the 12 volt battery at this point ... what's "pretty low" depends on what question you're asking. If the question is "does this reading indicate my battery could use a nice charge?" the answer is sure, go ahead. If the question's is 11.6 "pretty low" for starting the car, the answer's "nah, nowhere close to a problem." Some of the computers will start to (correctly) log notices about it, when it gets down around 9.
     
  16. TMR-JWAP

    TMR-JWAP Senior Member

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    Just for clarification......when you remove the 12v battery and the 12v system in the car goes to zero volts:
    1. The fuel gauge will go to one flashing dot when power is restored, until it resets itself. I've seen the 04/05 models take from 5 minutes to 5 days to reset. The 07-09s have typically been much quicker to reset.
    2. The car ecu's lose any learned values and go to default settings. This can sometimes cause the car to not start if a learned value was significantly different. For example, throttle body positions. There have been times where the car would fail to start due to the throttle position being out of expected position from carbon buildup. This is one reason why I stopped disconnecting the 12v battery when doing HV battery replacements. I'm doing an HV battery, not a throttle body cleaning service.
    3. The radio will lose it's presets
    4. The driver window auto up down will stop functioning. It can be restored by running the window up and continuing to hold the button for a few seconds to let the car "learn" the window position.
    5. Part of the "ecus going to default values" includes the HV battery SOC indicator. It does not display the last known value, it displays a default value, until it has a chance to determine the actual state of charge. This is why you can fool the car into trying to start the car, even when the battery is below the SOC that would normally not allow a start sequence. Unfortunately, this "reset to default" often allows DIYers to unknowingly completely deplete the HV battery.
     
  17. pasadena_commut

    pasadena_commut Junior Member

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    I wonder if the gas in the tank went off after sitting for so long and the amount you added was not enough to overcome that? It also sounds like there are electrical issues, but misfires do seem like a possible result of using bad gas. Perhaps have a mechanic siphon all the gas out of the tank, put in half a tank of new gas, and see if the misfires go away?
     
  18. ChapmanF

    ChapmanF Senior Member

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    I didn't see this earlier, but it seems dubious to me; is there a reference?

    For controlled discharge of a NiMH cell, 1.0 to 1.1 volt is usually regarded as fully discharged (corresponding to 168 to 185 volts for a Gen 2 battery). As far as I've heard, the ECU locks out starting attempts somewhere around 20% charge or maybe lower. I don't know where 20% charge falls on a voltage scale, but I wouldn't have guessed it would be above the cell's nominal voltage...

    That's an idea, but the misfire code must have been stored from some time when the engine was running. As the OP started this thread with the car not even willing to go READY and start the engine, it seems the first order of business will be to find out why that is, which generally begins with reading the hybrid-control ECU's codes.
     
  19. dolj

    dolj Senior Member

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    This was based on my understanding that the ECU will not try to start the car once it is 39% SoC or lower, but I have no reference for that. I'll happily bow to your superior knowledge if you know it is more like 20%.
    My guess would be ~208 V, then.
     
  20. ChapmanF

    ChapmanF Senior Member

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    I think I had my Gen 1 down close to 20% one time when the engine was being cantankerous and not wanting to start ... I figured I was pretty close to the limit, when it finally caught. It was definitely a lot lower than 39%. Gen 1 though.

    As I understand it, NiMH chemistry doesn't give a nice linear decrease in voltage with discharge, as some other types do. It holds fairly steady for a long time and then drops fast. So I'm not sure there's any easy way to say, oh, X volts is Y state of charge. I think that's one reason the battery ECU has a current sensor, and counts coulombs in and out, and other smart chargers use tricks like ΔV or temperature as a way to tell when they're done.

    Edit: I put a perfectly good 'delta' character in front of that V, and the PriusChat censor ate it. We're censoring math symbols now?

    Edit 2: ok, I used an ordinary Greek capital delta instead of the math one, and that's acceptable, I guess.
     
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