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First Maintenance Problem, Need Help Troubleshooting

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by lee, Mar 3, 2009.

  1. lee

    lee New Member

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    I have a 2005 Prius that's just a few months out of its warranty, though I do have the Toyota Platinum extended warranty, which I purchased through this site. I'm having my first genuine problem with the car, and I'm hoping someone here has had something similar or has an idea what might be wrong. I typically do my own maintenance, such as oil changes, tire rotations, etc, and I like to have a pretty good idea of what needs to be fixed before entrusting my car to the dealer because I've had trouble in the past when I didn't.

    The problem is that my 12v battery is discharging. My tip off came when the exclamation point started appearing when I was turning on the car, and then one morning the alarm went off by itself in my garage and I couldn't disarm it or unlock the doors with the SmartKey. At that point, the battery was down to about 9 volts. I was able to recharge it using a trickle charger and get the car working again.

    Using a clamp on DC ammeter, there seems to be about a .5 AMP drain even when the car is off and all the dome lights are switched off, but with the back hatch open (even if I press the latch switch with a screwdriver). When the car is on, I can see that current is flowing into the battery and that the battery is being charged and the charging voltage is a healthy 14v or so. For now, I'm using a Battery Tender when I'm not using the car to keep it from going completely dead. If I don't, the battery's voltage slowly drops.

    I do have two small electrical mods to my car, both dating to about when the car was new -- a VAIS AIC-100i for iPod connectivity, which I've disconnected since this has been happening, and a small inline device for defeating the Navigation lockout, which I've left connected since it's harder to reach. I also have the factory block heater, but rarely use it.

    I've noticed that the pump that makes noise when the car turns off to save the hot coolant sometimes runs and sometimes doesn't, whereas it used to always run. I'm not sure if this is related to the problem or not.

    I hate to replace the battery, which the dealer will probably insist on, when it seems that the real problem is that something is drainig it. I could easily replace the battery myself, but would hate to spend the $100+ if that's not the real issue.

    Any help would be greatly appreciated.

    BTW, since buying my car, I've directly influenced two friends/family members to purchase their own by taking them for rides, sharing my mileage statistics, and otherwise being a Prius evangelist.

    Lee
     
  2. paprius4030

    paprius4030 My first Prius

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    :noidea:I bet it's the battery
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The quiescent current drain should be more like 30 mA or less. If your car is really incurring a 500 mA current drain, this explains the problem. However you need to close the hatch before measuring since the courtesy lights in the doors will be on while the hatch is open.

    So, close the hatch and see what quiescent current is flowing. If it is much more than 30 mA and you are sure that your measurement device is correctly calibrated (perhaps you may want to confirm the measurement using a good digital multimeter) then you'll probably have to start pulling fuses to see which circuit is causing the excess current drain.

    This activity will probably set DTC fault codes, so then you'll have to disconnect the battery negative terminal for a few minutes to clear the codes.

    If the quiescent current drain is normal, then the answer is simple: replace the 12V auxiliary battery.
     
  4. lee

    lee New Member

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    I have all of the lights switched off manually and have measured the current with both the hatch closed and with a screwdriver depressing the button to simulate the hatch being closed, and it's always about .5 A current drain. I'm using a high quality digital clamp-on ammeter. I haven't used an in-line ammeter, yet, but I have no reason to mistrust the clamp-on unit.

    Pulling fuses is on my list of things to do next, but I was hoping that this might be something that's been seen before.
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    OK, I assume that no lights are on and the instrument panel is dark. I further assume that you hear no continuing noises being generated by the car. (If you do hear some noise, then it would be good to figure out where that noise is coming from, since that is likely the source of the current drain.)

    Maybe you might start the troubleshooting process by pulling relays instead of fuses, since that is potentially easier. If the IG1, IG2, IGCT, or EFI M relays are stuck closed, that might explain ongoing current draw.

    If that doesn't help, then you'll probably have to pull fuses. Good luck.
     
  6. jayman

    jayman Senior Member

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    A 500 mA drain? I hate to bring this up, but since Yours Truly has made the same error, are you sure you're on the correct scale?

    You can either get a 24 hour Toyota Techinfo subscription, or a 12 month All Data subscription, to get the electrical troubleshooting flowcharts. They are a very good reference for diagnosing a problem like this

    If you don't mind waiting half a day or so, I could look into this further and try to point you in the right direction
     
  7. lee

    lee New Member

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    Yes, it is the correct scale, as the meter only has one scale, 0-660A DC. I'm going to measure the current drain in-line tonight with an even more precise Fluke meter as a double check. I didn't do it earlier because I want to put a power supply in parallel while I'm disconnecting the battery to store all my various radio presets, etc.

    I'd welcome any assistance you can offer. I probably won't take it in until next week.
     
  8. EZW1

    EZW1 Active Member

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    I agree the battery is likely bad. When a battery starts to go bad, you can pump all the charge current you want into it and it will not hold the charge. In advanced stages the terminal voltage starts to drop off and you get in trouble.
     
  9. jayman

    jayman Senior Member

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    It has been my experience that the clamp-ons with a high scale tend to very poorly determine <1 A current. A very expensive power meter, like my AEMC, will not only determine <1 A draws, but also very high loads with very tight accuracy

    One way to check the battery: remove the battery from the car. Fully charge it with a regular battery charger. Let it rest 24 hours so the surface charge is gone. Check voltage with a good DMM

    If you're under 12.9 vdc, that battery is done. Consider the Optima replacement from elearnaid, about the same price as a dealer battery but much better quality

    12 Volt (12v) Toyota Prius Auxilary Battery for 2004, 2005, 2006, 2007, 2008 and 2009 with installation kit and free shipping

    If you suspect the current battery to have a dead or shorted cell, replace it ASAP
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, I agree. If the meter range is 660A, then a 1% error is 6.6A - so what we are talking about is well into the noise level. I would say that the readings of this clamp-on meter cannot be relied upon, and that it is necessary to use a good inline ammeter to determine the small currents under discussion.
     
  11. lee

    lee New Member

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    Ok, I'll measure it with an accurate inline ammeter and let you know what I get. I'll also try leaving the battery disconnected to see what happens to the charge over time.
     
  12. lee

    lee New Member

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    Ok, I disconnected the battery last night and performed several tests and measurements:

    1) Current with hatch open, all lights turned off: 0.5 A (my clamp-on meter was right)!

    2) Current with hatch closed, SmartKey in the house away from the car: 25 mA.

    3) Charged battery overnight, while disconnected from car. Connected it up for a few seconds to dissipate the surface charge. Measured voltage: 12.56 V

    So, it looks like I don't have the excessive drain that I thought I did, and that, based on earlier recommendations, I do need a new battery.

    My next question: is it worthwhile to get the Optima kit from eLearnAid.com for $180 vs. an OEM battery online for from ToyotaPartsCheap.com for $122? Since the Optima is 50% more expensive, it would have to be good for at least 4.5 years for it to be worthwhile. Thoughts?
     
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I suggest that you leave your battery alone for a couple of hours, then measure the voltage again. I suspect that it will continue to show a voltage decline. Further, a better test is to see what is the battery voltage when the car is IG-ON (not READY, where all instrument panel lights are on.) That puts the battery under some electrical load.

    Glad to hear that your problem is easy to fix. Perhaps you should call the Toyota source to see whether they will ship batteries; and if so what freight cost will be. If they will ship, my guess is that freight cost will eat up much of the difference in price. You may be better off calling Toyota dealers in your area to determine their prices and buying locally.

    Many posters have bought Optima and been pleased; however no one has owned it long enough to say for sure that it will last longer than the original equipment GS battery. In my case, I plan to buy another GS battery from a local Toyota dealer this coming winter for my 2004, since the original battery will be 6 years old then.
     
  14. lee

    lee New Member

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    Before connecting battery to car: 12.56 v
    After connecting battery to car: 12.42v
    Accessory mode (one press of Start button): 12.01v
    Ig-On (two presses of Start Button): 11.1v

    Local dealer price of battery (includes tax): $151.20
    eLearnAid.com Optima kit (includes shipping, no tax): $180.00
    ToyotaPartsCheap.com (includes shippping, no tax): $122.00

    The one downside to the Optima is that it will take about a week to get via UPS ground, but my battery seems to be usable until then assuming I keep it on the Battery Tender at night or use the car more frequently.

    I have no idea why my OEM battery only lasted 3 years + 3 months. The car only has about 30K miles. That's the one part that worries me about getting another one. My other car's battery is almost 9 years old and still going strong (though the car only has 13K miles on it).
     
  15. narf

    narf Active Member

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    A good auto shop can load test the battery. That's the only way to be sure of the battery's condition. however, if the battery has been deep cycled a few times it's life has been reduced anyway. I'm not sure, but I think some have had success with this battery also:
    WestCo Battery - Motorcycle Batteries and Marine Batteries
     
  16. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The voltages that you show in post #14 are not terribly bad. If I were you, I think I'd drive the car a few more days to see if the battery is going to die again or not. If it dies, then I'd probably buy the GS battery for $122.

    If you drive the car frequently and over long distances, this certainly will help to keep the battery charged up and in good shape. Your use of a battery tender will also extend its life.
     
  17. richard schumacher

    richard schumacher shortbus driver

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    The Optima should have a longer life, but we have little data so far. Also note that it takes several tools to install, and if you don't have access to a bench vise, considerable hand strength to dis-assemble the Toyota positive battery clamp.
     
  18. galaxee

    galaxee mostly benevolent

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    the battery in our 05 lasted 3 years 11 months. it still started the car, but was showing signs of deterioration so we waited until a convenient time. we only expected 4 years out of it in the first place, these batteries aren't the longest-lasting.
     
  19. lee

    lee New Member

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    I've been going through this for several weeks, now. The aux. battery has discharged several times (despite being recharged overnight) to the point of lighting up the warning sign, so I think its time has come.

    Tools are not a problem. As I mentioned, I typically do my own auto maintenance.

    The Miata battery doesn't look like a good choice to me for several reasons.

    I'll probably go with the Toyota battery. Maybe they've improved it over the past few years.

    Thanks to all the people who helped me with the diagnosis!

    Lee
     
  20. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    I'd say at over 5 years and 111k miles, mine is showing signs of declination. IG-ON voltage displayed in the MFD service menu is ~11v, however the battery is still "starting" the car. Most obvious signs are the panel and lights grow noticably brighter at startup, and the coolant pump motor speed (sound) increases once the brake pedal is released and/or the headlights (HIDs) are turned off. SKS at times is also unreliable.

    Still kicking myself for missing the local dealer 20% off parts sale a couple weekends ago. Most places I checked into won't ship OEM batteries due to hazmat concerns. Does the site mentioned further up ship ground?