This could be fun...

I've had three amigos ever since I got my 99 D2 in 2017 (younger, broker, clueless). I've restored just about the whole truck at this point, now I just have to battle 3 Amigos.

I started with the Option B bypass (ground one side of shuttle valve and splice other into the green/yellow on the modulator plug) - no dice. Since I do everything backwards, I checked continuity on the shuttle valve switch itself. I had 3 ohms consistently, even when I pressed down on one or both sides of the switch (from what I hear, it's supposed to go to 2 ohms when I press a side and 1 ohm when I press both). Finally, I bought an LR code reader and checked it out because I didn't want to replace the shuttle valve for no reason... I got 12 codes in return:

0204 - ECU Ground or Reference Ground Fault
0140 - Shuttle Valve Switch Long Term Failure
0308 - Front Left Outlet Valve Open Circuit
0320 - Rear Right Outlet Valve Open Circuit
0420 - Rear Left Sensor Output Too Low
0440 - Front Left Sensor Output Too Low
0480 - Rear Right Sensor Too Low
0680 - Rear Right Sensor Electrical Failure
0820 - Rear Left Sensor Signal Erratic
0840 - Front Left Sensor Signal Erratic
0880 - Rear Right Sensor Signal Erratic
0B10 - Shuttle Valve Switch Electrical Failure

The help I need is to decipher these codes. I can't tell if one of these problems is tripping everything, if they're all issues, solutions? Let me know if I should try anything and I'll give it a shot. If anyone can link another thread that'll help me out, I'll go ahead and delete this one, don't want to oversaturate.

Thanks guys,