NEED HELP ON CODES 21 AND 15

[MRH3542]

I'm helping a friend with a 07 Firebolt 1200 that has the check engine light on . We pulled the codes using the jump wire and we believe they are 15- IAT and 21 Muffler control module. Can any one tell me if this is a common problem and could something else be causing both of these codes???

Thanks,
Mike

 

[xtremelow]

Sounds like they are just unplugged. Did you take the air box off to see if they are both plugged in?

 

[MRH3542]

Yes both are pluged in