No pulse to #3 code p0203

[XLexusTech]

No pulse to #3 code p0203
LS3 Crate motor, PSI harness and ECU. Car starts and but run throws a p0203. Checked injector signal with node light no pulse header tube is cool on #3
12Volts to the pink wire at injector key on and while running.

I assume the only thing that could cause is this break in the ground side (tan) bad connection to pin 38 on X2 (GRAY) or a bad ECU..

If I am on the right track then Ohm out the tan wire to the pink / black in pin 38? If good then it must be ECU ?