New 12 Volt Battery Installed

[cbuck]

I took my 2007 400H in for a oil change and the Toyota dealer said my battery needed to be replaced as it was really low on cold cranking amps. After they installed the battery it would take at least two tries to start the car. A call to the Lexus dealer suggested a new battery in the key fob and then two days later it would not start at all. Connecting the battery to a charger showed that it was low and needed a charge. My old battery was working fine when I took the car in. Does anyone have an idea what could have happened?

[1990LS400]

I can mainly tell you what has caused low battery charges on our Toyota/Lexus cars:

* Corroded battery cable clamps - they should be spotless clean and bright and shiny where they contact the battery terminals

* Cracked battery cable

* Failing alternator

* Failing starter

* A loose/defective ground or problem in the circuit between the alternator and the battery

Early this year my 00 LS400 was sometimes starting slowly, would take repeated attempts and sometimes the engine would die in traffic. It acted like a bad battery but the battery always charged back up to full charge when put on a battery charger. It turned out to be a failing starter that was drawing a massive amount of amps with the battery never getting a chance to recover on my short daily commute. The amount of amps a starter draws is easily tested so a repair shop shouldn't have to guess if that if the problem.

If your old battery was the original one, I would have replaced it too without much or any diagnosis since getting seven years out of battery is very good. I've had name brand batteries last as little as one year and one was defective right off the shelf.

If replacing the car battery with a new one immediately caused your car to barely start or not start at all, the first thing I would suspect is a defective battery cable or clamp - items that would have been disturbed during the replacement. Was your car starting properly when you took it in for that oil change?

I think your best bet is to return your car to the repair shop and let them diagnose the problem.

[cbuck]

It was working perfect when we took it in. Dealer is saying it's just a coincidence.

[pj8708]

There is no such thing as a coincidance in your story. It either works or it doesn't. To suggest it might be the battery in your FOB seems screwy to me. I would follow Jim's suggestions to the letter.

Good Luck.

Paul

[cbuck]

Thanks! The dealer had cleaned the battery post but not the cable. It appears that was the problem (car started first try after cleaning). I will know for certain in the next couple of days.

[SOMEONE ELSE'S GOT MY NAME]

I took my 2007 400H in for a oil change and the Toyota dealer said my battery needed to be replaced as it was really low on cold cranking amps. .......................snip........................

Does anyone have an idea what could have happened?

Yes,

The Dealer blew smoke up your nether region. Your 12v Aux battery does NOT have - not does it need to crank the 400h. It merely boots up the ECU's. When the ICE starts, it's the MG's that starts it up. That's not to say your 12v battery wasn't low. They're awfully undersized - because they don't need a lot of power to simply boot up the ride. But because it's a light weight battery to start with, it takes way to little electrical draw to kill it. Think dome light on all night ... or running the music player while working on it ... stuff like that. We changed over to a 12v battery that actual DOES have cranking amps, so we can avoid the all too common scenario of aux hybrid battery premature death. I would highly advise on NOT getting a Lexus OEM battery, as you'll end up getting overcharged, for an under rated battery

[dian11]

It was working perfect

[pauloil]

whenever you put new battery, get a battery tool and clean the inside of the clamps, the posts.  look at the wires where they join the clamps.  if needed, do a voltage drop test on the starter wire, the pos. battery wire, and also the neg. side

[virtualking]

You have received a faulty battery perhaps you should Ask for the replacement and get a new one