Problem solved, light is off !!!!!!! Thanks for all of your help. Here is what I did, a bit out of the box, but it works for my purposes. Remember, the input speed sensor is an AC generating permanent magnet sensor; the faster the toothed gear moves, the greater the frequency and amplitude (mine did not work at all). Well the ABS brake system has the same PM sensor on each wheel, just smaller. I tapped into the right front wheel sensor when I was driving and it generated approx 1.5 - 2 VAC, which was in spec. Knowing that signal was working, I simply tapped into that circuit, built a very simple voltage tripler circuit, and fed that into the cars computer (PCM). Success !!! The "Check Engine" light went off and stayed off. Just to confirm it worked, I temporarily disconnected the circuit and the light came back on within a few hundred feet. I reconnected my tripler circuit and the light again cleared itself. Lessons learned: all this time I thought the computer was looking for a sine wave AC frequency. This must not be the case, since my understanding is the tripler output is a DC square wave. Very simple solution and I will pass it on the the other Cadillac guys. Hey thanks to everyone for the help and suggestions. We did it !!!! ("Yo Adrian, we did it !!! ")

 

That tripler is producing a DC voltage output, not a square wave!

 

That tripler is producing a DC voltage output, not a square wave!

I must be a bit confused. I thought AC into the circuit and DC out of the circuit would be a square wave. Are you saying that the wave is sine, because the source voltage is AC? If so, I stand corrected.

 

I must be a bit confused. I thought AC into the circuit and DC out of the circuit would be a square wave. Are you saying that the wave is sine, because the source voltage is AC? If so, I stand corrected.

The output will be a steady DC voltage, no AC component at all other than a small ripple depending on the load on the tripler output.
http://www.physics-and-radio-electr...pliers-voltagedoubler-tripler-quadrupler.html
"The voltage multiplier is an electronic circuit that converts the low AC voltage into high DC voltage."

 

The output will be a steady DC voltage, no AC component at all other than a small ripple depending on the load on the tripler output.
http://www.physics-and-radio-electr...pliers-voltagedoubler-tripler-quadrupler.html
"The voltage multiplier is an electronic circuit that converts the low AC voltage into high DC voltage."

Just curious, which wave form does the tripler circuit output? I want to know what the computer actually looks for.

 

No waveform, just a DC voltage.