A bad diode will not cause a switch to show stuck.
Quoted from Occelot:What's weird is... I totally removed the 02 wire (brown w/white tracing) form the MPU. But it still throws 02 in the switch test. When I remove the entire connector from the MPU, I do not get the 02 message. I get 0.
Switch 02 lives at the intersection of St-0 and I-1. Neither of those is a 65 (brown white) wire. I1 is 63, brown yellow and St0 is 51, white red. Did you repin J2? it sounds like you have wires crossed.