Slightly resurrecting a dead thread (but hey it's a sticky):

The temp for CAT Diagnostic Enable Coolant Temp should really be like 285 instead of -285. The diagnostic will run anyway if it's set to -285 because it will always be above that temperature. It would happen once every drive cycle for me until interrupted by hitting the gas hard or something (the wideband would go way rich, like .68 lambda). After it was interrupted, it wouldn't run again, but it was still annoying. Setting it to a high positive number has kept it from coming back.