1099R public safety officer question

[Smokin Joe]

I was employed as a police officer and retired after 26+ years on a disability pension ( before minimum retirement age). I have since passed minimum retirement age years ago. My 1099 R indicates $0 on line 2a for distributions and code 3 ( disabled) on distribution code. Inadvertently over the years Ive always included my pension as taxable income. Should I be exempt from federal taxes on this pension since my 1099R indicates so.

Thanks for any help.

[SharonD007]

Yes, this is non-taxable income since the amount in box 2a is $0 and your distribution code is 3.

[Smokin Joe]

Thank you Sharon. I appreciate your interpretation. Ive mistakenly been including that in my total federally taxable income. 
Thanks again.

[pudave]

you can amend the last 3 years to remove it