2002 Mitsubishi diamante battery won't stay charged. I had Sears check it out and they said the charging system works just fine and charged the battery. Didn,t drive car for 2 days - it was in a nice warm garage and had battery checked again by auto zone and they said it had only 4 volts left. does the diamante have charging problems? or is something causing the battery to drain

This problem may be a drain or a bad battery or alternator.

The first thing to do before going on trying to find the system that is draining the battery would be to have the battery tested and charging system tested.

A weak battery will seem ok after the car is jumped or will barely start the car and the alternator will charge it even though the alternator is overworking due to weak battery and during the day or when car does not sit long it will seem ok. then when car sits overnight or a few days battery will weaken on its own, making it look like a drain,

so first step is battery test and alternator/charging system test.

Charge it all the way up. Then take it to a auto parts store and get the battery and starter and alternator tested.

have the charging system checked out find out if its charging anything.this may have been why the battery light stays on.usually a bad battery won`t turn on the battery light as its used to let the driver know that the charging systems needs to be checked out.

Check your fuel system: From might be dirty: Spark plug, Fuel filter, fuel pump, fuel injector, EGR and your high voltage and also your distributor check it also. Some the computer box faulty..

It sounds like you need a new starter. If you hear the starter click when you turn the key to start, replace your starter since you already replaced the battery. You might want to have your alternator checked out, or when you get your car started, test the battery terminals with a multimeter. You should have around 14 volts with the car running. If not, you will need a new alternator. The alternator won't keep the car from starting though, unless the battery was drained because it wasn't charged. Even then it is the battery keeping the car from starting.

If the starter is not clicking, check your fuses under the hood. If all checks out, you may have a bad ignition switch.

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

sound like might have a prooblem with the charging system. if the altenator is not charging the battery while driving then when the battery voltage gets too low (prob around 10volts) then the computers will shut down, then when jump started it gets some power back, and when the battery is charged will all work fine for a while.
does your model have the voltage gauge in the dash? should be over 12 volts when engine running, 14volts is a good charge rate. and should stay up above 12 all the time, with lights on air condon etc...
and altenators can be funny, work sometimes, and not atother times,

have the battery and charging checked at a walmart or autozone before u shut it off.

get the battery and charging systmem checked to begin with. A low battery causes issues

i say charge the battery before trying anything else

if that fails temporaily replace the old radio and see if it starts

change alternator or check fuse