Parasitic current draw with ignition off kills battery when not started for a couple of days.
My car has 160000 miles.
My car has an automatic transmission.
Hi. The first thing to do is to look in the vehicle when the doors are locked to see if any lights are staying on. Do not overlook the hood light and map lights. The most common failure to cause the draw, since it only takes a couple of days, is the alternator shorting internally in the voltage regulator. If no lights are on, then the alternator will need to be inspected for possible electrical problems. If you need further assistance, I recommend you have a certified technician, like one from YourMechanic, replace the alternator if it is diagnosed to be the problem.