OK, so my problem was a bit different. Turns out it was a wiring problemo...
After reading this thread and checking my TOD error code, I received a "shorted ground" error code (#13). Looked under the truck at the TOD and started from there...
Long story short...It appears that the guy who replaced my catalytic converters and exhaust did a GREAT JOB on all that...however he didn't route the TOD wiring harness correctly once everything was finished. The wiring harness was laid up against the exhaust which melted through the wire sheath and shorted a few wires together. Once the wires were separated, repaired and secured properly, the TOD CHECK light went off and everything is back to normal.