1995 eclipse dies and wont start for A while code says exhaust sensor. but it drags down battery like it's the alternator.

if you want to check to make sure the alternator is charging yourself hook up a voltmeter to the battery positive to positive, negative to negative and start the car. The battery voltage should read 14 volts to 14.8 volts due to the alternator charging the battery. Then turn your headlights on if the voltage drops below 12 volts in the alternator is not properly charging the battery. Make sure you have no corrosion on the battery post. You can also do a voltage drop test by connecting the positive lead of the voltmeter to the alternator positive post and the other voltmeter lead to the positive post on the battery if you have a drop in voltage more than 0.02 you might have a diode open and the alternator. If you do not have a voltmeter then you can take the car to a parts store such as Advance Auto Parts and they can check your battery charging and starting system on the car for free.