Check the build date code of the IC. The date code is displayed in the message center during "engineering test mode".
Engineering Test Mode:
Ignition in "OFF" position.
For Base Clusters (without message center cluster): depress the reset stem on the cluster while turning the ignition switch to the "ON" position.
Message Center Clusters: depress the reset button in the vehicle while turning the ignition switch to the "ON" position.
Continue to hold down the reset stem/button for 5 seconds until the cluster message center displays "engineering test mode".
Press/cycle reset stem/button until the message center displays "manufacture" and the date of manufacture (MM-DD-YYYY).
If the date is after 12/22/2006, this TSB does not apply and proceed with normal diagnostics found in Workshop Manual (WSM), Sections 413-01 and 413-08.
Turn the vehicle ignition to the "OFF" position to exit the "engineering test mode".
Outside Air Temperature (OAT) Diagnostics
Cant recall, but in test mode you can cycle through all the system monitoring options.