I had a thought. Perhaps the bulb is burned out. This could particularly happen if the CEL had been on for a long time.
The unfortunate part is that these bulbs are not the twist to remove type that have been used in the past. They are soldered in, making replacement a bit more involved.
It certainly could be worth testing the bulb if you really want the functionality. If you don't like to fool with it yourself,
Southern Electronics in Richmond, VA does really good work at an affordable price. Turnaround is fairly quick, too.
Good luck!