Virulent

iTrader: (2)

Need help figuring out what is wrong with the car.

I think it all started when I made a lot of short trips with the car. I used my car to drop off my son less than 1 mile to school (hey, it was cold). My son had an emergency and I had to pick him up from school, then bring him back again. It was a total of 6 short trips, less than 1 mile each time and happened within 2 hours time. That night, the original battery lost juice, so I jump started the car and drove it for 45 minutes. After that, it started fine the next day. But when I let it sit over the weekend, the battery was dead again.

I assumed it was the battery and bought a new battery at Costco. Installed it and everything was fine, but I did not use the car over the weekend, and now the battery is dead again.

The only other thing I could think of is that my wheels don't have TPMS sensors on them at the moment.

Is it just the cold weather or is something running while the car is off?

The car is a 2008 put in service at the end of 2007, so the original battery is 4 years old. I don't use the auto headlight function. I do lock the car when its in the garage.

chino713

Thats kind of the problem i had and now when i turn on my car it start up real rough

chi123

iTrader: (12)

Something is probably draining your battery when the car is off. Short trips and cold weather shouldn't be an issue. I drive my car many times throughout the day only to go under 2 miles every trip.

Sango

iTrader: (10)

Maybe the alternator is failing.

Joeb427

iTrader: (1)

You definitely seem to have a battery drain somewhere.
No way the battery should die in 3 days or 3 weeks.

Slammer1

Sounds like either the alternator is failing and can't produce enough current to keep the battery charged or there is an electrical draw which is draining the battery. If it's the alternator, you should see issues when running lots of electrical accessories. Crank the car and turn on your A/C, stereo, high beam lights and turn signals. If you get a warning light on the dash under this heavy electrical load, I would think alternator. If there are no such symptoms, you are looking at a draw. Take the car to have the charging/starting system checked to be certain that isn't the issue. If it's good, you will likely end up at the dealer or an electrical specialty shop to find the draw that is draining the battery.

funglenn

iTrader: (10)

Mine is not driven for 2-3 weeks at a time right now and it holds a charge--just fine. I would think a failing alternator could be the cause of it.

Virulent

iTrader: (2)

I think I found what was draining the battery.

The trunk light has a switch that keeps it on even with the trunk closed (I peeked through the pass-through. So I turned it off and hopefully my battery will keep it charge now.

I did take my car to Autozone and they told me my alternator is bad because it was reading around 13.4V
I don't see how the alternator is bad because it still charged the battery and I don't experience any problems when I put a lot of electrical load while the car is running.
Can somebody with an IS350 measure the voltage at the battery with their car running. I'm hoping 13.4V is normal for this car.

carlos3366

13.4 is normal for most cars.

Sango

iTrader: (10)

Could be something wrong with your trunk switch shut off when closed because it is suppose to turn off when your trunk is shut. Just for kicks, I closed the trunk with myself inside when I switched to LED inside - opened the latch to let myself back out and lights turn on when open, since it was pitch black.