Battery problems -- theft deterrant system to blame?

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chris.mcgraw@gmail.com - 28 Feb 2006 04:00 GMT

My 1999 Toyota Camry has gone through a couple batteries now -- the
first time I just figured it was about time, and the second time (only
about 4 months later), I was suspicious but thought it might be
accounted for by my poor driving habits (frequent short trips). The
battery indeed had minimal charge, both times, when checked with a
voltmeter; I replaced it a third time, and after a week, the battery
was dead again.

Now I suspected the alternator, but when I jumped the car while
measuring the voltage across the battery, the voltage steadily
increased and plateaued over 12 V even after disconnected from the
jumper car -- so it appeared to be functional. At this time, I noticed
that the negative terminal on the battery had been loose, so I thought
perhaps the poor connection had been preventing some charging in the
days before it died. I let the car sit for about 4 hrs, and the voltage
across the battery was again down to about 2V (fatally low, I'm told,
for a battery). Given the supposedly "catastrophically" low charge
across the battery before I jumped and recharged it, I'm unsure whether
or not the speed with which it discharged is any indication of a
"drain" on the battery or whether it's now just inherently unable to
hold a charge.

I have a hunch that it should have been able to hold its charge a lot
longer, and that the discharge indicates something is draining,
possibly the theft deterrant system. So two questions:

1) Has anyone heard of problems with faulty theft deterrant devices
draining batteries? I've only owned the car since August, so I'd say
it's conceivable that this problem might arise now despite several
months of ownership during which I was in fact using the theft
deterrant system without noticeable problems.

2) Furthermore, does anyone know how to specifically disconnect the
theft deterrant system on a 1999 Camry short of pulling out fuses?

Thanks!

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Gord Beaman - 28 Feb 2006 06:05 GMT

>My 1999 Toyota Camry has gone through a couple batteries now -- the
>first time I just figured it was about time, and the second time (only
[quoted text clipped - 8 lines]
>increased and plateaued over 12 V even after disconnected from the
>jumper car -- so it appeared to be functional.

With the engine running at high idle your voltage across the
battery should be at or over 14 volts, it's usually around 14.5
volts but I'd sure look askance if was much less than 14 volts.

>At this time, I noticed
>that the negative terminal on the battery had been loose, so I thought
[quoted text clipped - 10 lines]
>longer, and that the discharge indicates something is draining,
>possibly the theft deterrant system. <snip>

What I'd do is jump it...then charge the damned thing well, maybe
a good long spin up the highway, maybe a couple hours (during the
day) then get someone to hold the engine at high idle (maybe 1500
RPM) and check the voltage across the battery, you should see at
least 13.5 volts, more likely you'll see over 14.

Now if all seems well, shut it down, make sure everything is off,
no lights on etc, take either battery terminal off it's post and
check the current between the post and the terminal that you
removed. If you're not familiar with an ammeter you can use a
small 12 volt bulb instead. (like one you'd find in the glovebox
etc). It shouldn't light. Remember that you'll lose the radio
presets etc when you disconnect the battery. Good luck (I have a
2000 Corolla which has never had the battery changed - nor
anything else either!)

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-Gord.
(use gordon in email)

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Ray O - 28 Feb 2006 06:07 GMT

> My 1999 Toyota Camry has gone through a couple batteries now -- the
> first time I just figured it was about time, and the second time (only
[quoted text clipped - 17 lines]
> "drain" on the battery or whether it's now just inherently unable to
> hold a charge.

FYI, if you discharge a normal battery too deeply and leave it in a
discharged state, it will lose its ability to hold a charge.

The alternator should be putting out somewhere in the vicinity of 14 volts
if the battery is deeply discharged and output will gradually drop as the
battery reaches full charge. Assuming that the battery clamps and
alternator connections are tight, have the charging system checked at the
place you got the battery if it is not putting out at least 14 volts on a
discharged battery.

> I have a hunch that it should have been able to hold its charge a lot
> longer, and that the discharge indicates something is draining,
[quoted text clipped - 5 lines]
> months of ownership during which I was in fact using the theft
> deterrant system without noticeable problems.

There is nothing in the factory theft deterrent device that can cause the
battery to drain in 4 hours unless it is constantly blowing the horn and
flashing the lights, and even then it might last longer. I have never heard
of the factory security system causing that kind of drain. That is a pretty
quick drain and if you are purchasing cheap batteries, it is just possible
that you are getting bad batteries You can hook up an ammeter and measure
the drain on the battery. Normal parasitic drain should be measured in
milliamps. If you are getting more, you can pull fuses one at a time until
the drain stops. Things to check first:

1 - aftermarket audio system if so equipped
2 - aftermarket security system if so equipped
3 - aftermarket power socket and accessories hooked up to the power socket
4 - aftermarket lights like fog lights, "mood lights" if so equipped
5 - stuck power door lock solenoid
6 - light on somewhere, like glove box or trunk

> 2) Furthermore, does anyone know how to specifically disconnect the
> theft deterrant system on a 1999 Camry short of pulling out fuses?
>
> Thanks!

Sorry, I've never tried disconnecting the theft deterrent system on a 99
Camry.

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Ray O
(correct punctuation to reply)

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