Hi Don I spoke to ya today on the phone about the optimax 225 with wiring issues when checking the TPI sensor (unplugged) with a digital multimeter results are as follows black meter led to blkorange wire red meter led to light blue white -4.81 If I remember correctly you said blkorange was a 5volt ground I also checked purpleyellow (red led) to light blue white (black led) which showed 4.88. Considering the wiring issues that I have corrected and going by the polarity my meter is showing is this an indication my ecm is fried and instead of being 5 volt ground it is shorted to 5volt reference inside ecm