EOS Rebel T5i ISO not working properly

[VirginaTaylors]

I have a Rebel 5Ti. Love it and have never had an issue with it until 3 days ago. In manual mode, I use auto ISO. My photos are either black or very overexposed. In full auto mode they are overexposed. When I set ISO in manual the lighting is either very dark or overexposed even when the ISO is set appropriately.

I have cleared settings. Twice: In the hope that would fix the problem. No luck. Any other ideas?

[Tintype_18]

The overexposure in auto mode is puzzling to me. I'm sure others will chime in here.

Edit: I have a T7 and will see what I can find on my camera.

[VirginaTaylors]

Thank you. 

[deebatman316]

It sounds like the lens aperture isn't always stopping down like it should. Causing over or underexposed pictures. Do you have another lens to test on your camera. It doesn't have to be the same exact lens. It can be any Canon brand EF or EF-S lens. As a quick test set the camera to Av Mode and set the aperture to F/16. Then press the depth of field preview button. The lens should stop down and the viewfinder should Significantly darken. If it doesn't there's a problem with the lens. Or if the camera throws an error tell us the exact error code. Or take a picture of the exact error code the camera displays on the rear LCD screen.

[VirginaTaylors]

I tried a different lens and the same issue occurs. I will try your other suggestion and report back. Thank you!