3 Amigos - Help me Hunt!

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,

Don't panic... First thing to do is (find) check and clean all your grounds (earths?). There is one in particular in the area of the driver's side head light (It's been a while so I can't be exact, and my two D2's were in a different places). Loss of this ground will cause havoc with the anti-lock. Find the ground and clean well, I always put metallic anti-seize on ground connections to prevent any further corrosion and give a good connection. Anti-seize also works well preventing corrosion on the battery posts. Oh, I have both a '99 and a '03 D2, so been there done that. Also try 'Discoweb' a little more specialized on Discos.

Thanks for the reply - I'll go clean those grounds and let you know how it goes!

I see on DiscWeb you're 75% ahead on your problem. Hopefully that will make it easier to get things sorted.

Looks like I didn't post a conclusion on here - apologies. The grounds just behind the US driver side headlight were the culprit for most of the codes. I did need a new shuttle valve and a pair of ABS sensors. Thanks for the help mearstrae.

Good deal... You might also try doing the external wiring for the shuttle valve. This seems to prevent the three amigos from popping up at random times. Should be detailed info on Discoweb for this fix.