Code d6 or PO 500

[bostogrun]

I have three lights on the dash TC, ABS and CEL. I troubleshot the ABS and discovered a bad relay. For the time being I pulled the ABS relay and the TC and ABS lights went out. The CEL for d6 or PO 500 (no speed sensor input) stays on even after clearing it. The car runs fine sans the CEL the spedo works and it shifts fine?

It's my understanding that the speedo and tyranny get their inputs from the speed sensor in the differential.

By the way I did do an attempted check of the wheel speed sensors but because of the difficulties of reaching the pins deep in the cylindrical connectors.

Any knowledgeable input would be greatly appreciated