Hi. My name is*****'m a camera repair technician with almost 30 years in the business and I'll be glad to help you with your question today.
If there is a scratch on the low pass filter it will need to be replaced by Canon Service and the cost is determined by Canon at the time of the repair. In other words, they will provide you with an estimate for the repair first. In the U.S., this usually runs over $500.