I just swapped my 85 mph cable driven spdo for a 120 electric one. There is a connection that went to my old spdo that I guess sends a signal to the ECM that tells it what speed the car is going.
Now that I don't have that connected anymore my check engine light comes on.

Does anyone know what the signal is? Can I connect my electric spdo to that connector? According to my shop manual the connections are 12v, ground and an input signal. What input signal?

The new spdo works great but I hate having that light on and don't want to have to pull the bulb.

Thanks for your help.

 

Did you run the code? Much easier if you did that and then go from there. It'll give you a starting point.