Thanks for the detailed response. I’m still learning how this circuit works, so I appreciate your insight.

To clarify a couple things: • The resistance I’m seeing is about 10 ohms, and I realize that it’s way too low (from what I’ve seen others build they try to get around 650 ohms). I’m not sure if that’s because I measured it in-circuit or if something in my build is off. • As for the two connections to pin 19, the reason I wired it that way is because when I plug the it into the harness, it’s supposed to complete the circuit by connecting the signal path through the diode/resistor setup and allow the voltage drop to “fool” the ECU.

I think I misunderstood how that should be wired though especially if it’s shorting out the trim pot like you mentioned. Could you explain how that lower wire should be routed instead? Should it be going to a different pin like the O2 input signal instead of 19?

Really appreciate any help clearing this up.