I am planning to travel to the US on an Indian passport. My passport is overall in good condition, but with one defect: It cannot be properly scanned at the airports. So far, I have traveled quite a few times through China and Korea without any problems. But can this create problems for me while entering the US?
Given that it seems that you haven't even applied for your visa yet, it would be highly recommended to apply for a new passport first.
A machine readable passport is technically a requirement for entering the US, as well as for obtaining a US visa. Now technically you have an machine readable passport - just one that for some reason can't be read by a machine.
The "machine readable" strip on the passport is actually very simple - and thus the fact that yours apparently can't be read is at least suspicious. At a minimum it implies that your passport has been damaged somehow. At both your visa interview and (if you make it there) at the US border I would expect them to be very suspicious of a passport that will not scan. At a minimum, I would expect you to be sent to secondary screening whilst they attempt to confirm that your passport is valid and has not been modified in some way.
Although it's certainly possible that you will be allowed obtain a visa and enter the US with this passport, the simple answer is that it's not worth the risk. Get it replaced - at a minimum it'll likely save you some time at both the US consulate and at the border.