Weird Corolla electrical issue

[Bioguy]

Hello Toyota Forum!

Ok, let me preface my plea by saying I know almost nothing about cars, and this is not an accident. I hate working on them, but then it comes back to bite me in the butt because I am so ignorant.

I was wondering if someone here might point me in the right direction to what is causing my problem. Here are the symptoms of my 2003 Corolla:

1. Three days ago my car stereo started losing its "memory". That is, it no longer remembers preset stations, tracts on CDs, etc. When this happens it is always in the "off" position so it appears it is losing power from the car battery when the car is off.

2. This only happens when the car has sat for 24 hours or more.

3. The car's dashboard clock is unaffected (keeps correct time)


Seems like it is isolated to the stereo except...

4. After sitting for 24 hours or more the car battery does seem "a bit" weaker. What I mean is, there is a small, but noticeable, delay in the starter turning over. Kind of like starting in very cold weather. I know this part isn't just in my head, because I noticed this before the problem with the car stereo.


I'm confused because I don't see how there could not be enough juice to keep my stereo from losing its memory, but plenty to start the engine? And, if it is just a problem with wiring of the stereo (or the stereo itself), then why is there a change in the power of starter?

Any information would be helpful. Thanks for reading.

[FinalGear]

Did you replace your stock stero?

[Bioguy]

Sorry, yes I did. About six to nine months ago, and I had BestBuy put it in.

[adsaba1969]

It's not a battery issue, it's a stereo issue.

[Bioguy]

Thanks adsaba1969, but why would I have a noticeable drop in engine startup? Seems like quite a coincidence, no?

I am actually hoping it isn't the stereo, as that will probably end up being more expensive.

[adsaba1969]

Check the power wires for the radio. They're usually red and yellow, with yellow being the constant to aid in the memory. Make sure there is a sound connection. Also make sure they're not reversed or wired together.
Could be coincidence about the startup because 03-04's are know to have an occaional turnover issue. I'm not refering to the 05+ cold start issue (if you've been searching).
Rarely an aftermarket stereo will use a battery in the faceplate to retain memory but that is uncommon.

[Bioguy]

I will check that, adsaba. Thanks for replying.

I had wondered about a battery in the stereo itself. There is no mention of it in the manual, but those manuals are mostly worthless anyway.

[94_Rolla_Guy]

a car radio gets a constant 12V all the time 24hours a day then it gets switched 12V from the ignition to turn it on with the Key, may want to have the wiring checked out, there could be numerous things wrong with it,

also dont hesitate to check the fuses for the radio some cars have 2 some only have 1, some radios will have fuses inline in there power wires behind them too, its possible there could be up to 4 fuses for the radio.

as for the battery getting low enough for the radio to loose presets theres no way it would start your car after...

[REN69]

I had a similar problem with my battery just recently, my radio didn't keep all presets after turning the car off, but the car did start, slowly and weak but it would start, I changed the battery and the problem is gone now, turns out I killed the battery while I was doing my brakes the one day and had the stereo, amp, subs drawing power from the battery for a couple of hours.

Change your battery and see what happens, if the problem does come back with the replacement battery then your alternator is not charging properly anymore.

[Bioguy]

Thanks to everyone for the replies. This isn't even really a "corolla" issue, and I appreciate your help with this minor annoyance.

Because of work schedule I haven't yet had the battery tested, and because I am an idiot I couldn't figure out how to get the lid off the fusebox this morning.

I'll have more time later in the week to tinker myself and/or take it in for analysis.

But... here's another thing I figured out about it. If I turn the key in the ingition part way to turn on the stereo all the memory is still there, but as soon as I turn it all the way to hit the starter I can watch it become scrambled!

That makes it seem less likely to be a wiring issue (which all looks ok from my untrained eye). Does that point more toward a fuse, perhaps?

[Bioguy]

Thanks Rene69. That would be a good and simple fix.

[Bioguy]

Just wanted to close this thread out.

I actually did nothing for a few days. By the weekend it seemed clear to me that each day it was taking about a half second longer for the engine to turn over. That sure sounds like a battery going south... and it was.

Changed the battery and all is fine. Wish everything electrical was that simple.

Thank you so much for everyone that posted. I can see that some of the regulars around here can get a little tired of the noob technical questions. Understood, but it is very much appreciated.

[REN69]

Nice to hear we were of some help, keep an eye on the new battery though, if it starts happening again then you may still have a wiring problem somewhere.

[big_fella6699]

check the full time power wire, not the acc one, and make sure there is no visible damage, or the fuse( if it has one) isnt burnt out. if u can see neither of those... get an auto electrician 2 check it out