Check battery light

hello, I have a 2002 Toyota camry and for the last few or so, the check battery light has been coming on and off. it stays on for a day and then goes off for a day or so. I have had my mechanic check the battery, the alternator and he couldn’t find anything wrong with either of them. the alternator is working good, the battery tested at 730cca and 13.5volts. what is wrong and is it safe to keep driving this car? I would appreciate any and all response for this.
thank you


How old is the battery? If it’s older than 5 years, just replace it.

Is the drive belt in good shape?

Sufficient tension?

How many volts is the alternator putting out at idle?

What engine?

4-cylinder or V6

If the battery and alternator were properly tested and tested ok, then you likely have a problem with the signal wire for the dash warning light. Your mechanic should break out a wiring diagram, find the signal wire and check it.

But it’s also the case that things like loose, damaged, and/or corroded wires and connections can cause intermittent power problems. Was you mechanic able to check the system while the warning light was on? If it is an intermittent problem, then everything would test fine when the light isn’t on. Did the shop at least clean up and tighten and otherwise check all of your main power connections?

@db- the battery is 2 yrs old. its a 4 cyl and I am not sure about the drive belt. the car runs less and 1000rpm, around 800 when idling. don’t know how many volts the alt is putting out.
@cig-when I took the car to the mechanic, the light was off and no he didn’t clean or tighten the connections. should I do that first and see if it fixes the problem?


How many miles on the car?

Does the belt every make noise?

@db. I have 302000+ miles on it and sometimes in the morning when I start the car, there is a squeaking noise which goes away after a little bit.


Does the squeaking noise coincide with the battery light?

Check out this bulletin . . . you might already have the upgraded tensioner.

Your squeaking noise which goes away seems to match the symptoms described in the bulletin

I would take a closer look at that belt, also. If it’s glazed or worn, all bets are off

The problem can be caused by worn brushes in the alternator.

These are the brushes for your alternator. And from the looks of them, all that has to be done is remove the brush cover from the back of the alternator to replace them.


If that alternator indeed has over 300k miles on it I would just replace the alt. proactively.

Is it been a CEL (Check Engine Light or some other indicator?) A CEL should trip a indicator light and store a error coed that may be read by your mechanic.

This link may be somewhat helpful.