Long story short I have a 1990 formula with a built 355 and 700r4. Already swapped vss and code still persists. Speedo is electronic and doesn't work. Is the code just trying to tell me the speedo is faulty or are there other mechanical or engine related issues I should be worried about. With the exception of the speedo not working, the car runs like a dream. Thanks in advance. Pic of new vss same as old one pulled from transmission

 

You can measure voltage while driving at Vss buffer or ecm depends on what the car is or was tpi, v6 or tbi.

 

https://m.youtube.com/watch?time_con...b_title#dialog

 

It was a 350 tpi with ecm and no buffer. Still tpi

 

Check at b9 and b10 at the ecm yellow and purple white.
backprobe and drive looking to see if there is a signal. Yellow is signal purple is signal ground.

 

Rock on. In the meantime what are the mechanical ramifications of driving with a faulty vss. She seems to shift and accel fine

 

You could get stalling on deceleration and no tcc lockup.

 

Noted. I'll be on the lookout for those. Thank you