Couple of problems I need help with

[laserx]

First I have a 96 with no power light, but all of a sudden my AT oil temp gauge has started flashing 16 times on each start up?? Don't know what this means. This started last week. Then yesterday my CEL came on. I had my son check it out with his OBD2 scanner and he found nothing except one error message "Catalyst inefficient bank one P0420" but no error codes to work with.
Can anyone help identify the problem....and solution. The car seems to be running great, not problems at all, the CEL has been taken care of but still the 16 flashes. One a whim I changed out the resister by the battery since I had an extra sitting around, but no change. Thanks in advance.