As Zeracer asked, is this an SRT model? The P0239 code is typically associated with boost issues in turbo or supercharged engines. I think the most common DTC related to the secondary air pump, which is found on all Crossfires (well for sure on my 04), would be P410 - secondary air pump system malfunction. That is a fairly common code for Crossfures that is indicative of the failing relay control module (RCM). If that were the issue, i could let you borrow an RCM to see if it fixes things. But for P0239, might be a bad boost sensor, boost hosing, or electrical connection.