Can my Pell Grant be affected by taking courses not on my degree plan?

No.  The Pell Grant is only concerned with how many credits you are taking - not the names of the classes.

1. MOST colleges REQUIRE a certain number of elective courses.

2. The Pell Grant program has NO IDEA which classed are related to your degree.

You need to take courses that will count toward your degree.  Most degrees (and degree plans) involve some elective courses, which can generally be courses in any field of your choosing.  Otherwise, your funding CAN be affected by taking courses that don't count in some way toward your degree.

Yes, your Pell grant can be affected by this.  To receive federal student aid, you must be enrolled in an approved degree program, and the courses that you take must be able to be applied to that degree.  So, you could still receive aid for any courses you take that will be applied to the degree, but not for courses that won't be applied.  Since the amount of the Pell grant is based on enrollment status (i.e. full time, three quarter time, half time or less than half time), the amount you receive would only be based on the courses being applied toward your degree.  If the number of degree credits that you take is less than the full time amount for that degree, then the Pell grant would have to be prorated.   FYI, in response to some of the other comments,  the amount of the grant is determined by your school,  and yes, they DO know whether the courses you take can be applied to the grant.  They are required by federal regulation to adjust it if you don't meet the criteria for it.

1. MOST colleges REQUIRE a certain number of elective courses.

2. The Pell Grant program has NO IDEA which classed are related to your degree.

I believe you need to be enrolled as a full-time student and maintaining a 2.5 GPA. I don’t think they look at your course selection.