Fix one thing , break another - P1875

[thebanjoman]

Arduino, + ZCD , zero crossing detector is a must for VR coil sensors (most) as the signal  are tiny for sure low speed. of car. (a HALL sensor would be cake walk )

here is one example of the first part of the job, measuring frequency.

the next stop is scale up this new Freq. by 113% just using math.
freq-out = freq x 1.13  (now 13% more)
the set timer to freq-out


google how to use  Arudio to output a timer clock you control. (using freq-out)
and send it to a pin and connect that pin to VSS pin on TCM.

now the bad news, no spec on TCM
if lucky at least one pin might be ground and 2nd is input to TCM, vss1.

at the worse Ive done this and used transformer to emulate the VR sensor into TCM.
a 1:1 turns ratio transformer very very tiny one, 600ohms  rated, for audio work;.
I did the once to fool a FORD ECM to like my fake CRANK CKP sensor.

the VSS1 pins on the TCM
are not documented. pin # and color are, but not how TCM processes those pins, but in most cases is a ZCD in the TCM,   .

 Making changes at the trans speed sensor seems way above my skill level.

 Couldn't I make my adjustments on the speedometer side as that's what I am changing with my gear box device ?  

 Read the reed valve pulses and reduce them by 13%    ??