Little lady reported the dreaded 3 amigos on her way home from work the other day. Next morning she said they were gone. Brought home a borrowed snap on scanner and she had 2 codes (no lights on dash) of front left and rear right valve.

My electrical system knowledge of the disco 2 has been learned via trial by fire over the past year, however I thought the option b mod bypassed this. I did verify I have good ground.

I think this is usually a code thrown by a faulty abs module but before I go swapping them from my parts Rover (best purchase a Rover owner can make) I wanted to be sure I'm headed in the proper direction.

 

I could be off base here as I can’t recall the article (absolutely incredible write up by the author) for option B, but it’s my understanding that the valves are still in place and function, but something else is bypassed and the separate ground is what bypasses the design flaw and still allows all functions to work.

Also of note, I was taught that when you do option B, you should always start with a new shuttle valve. Hope that helps…

 

At 220k when purchased with what looks visually to have had a poor service history, @240k now, I doubt the shuttle valve is new. I have a 86k mile parts rig I can swap out with to verify.

I read into this when I did the option b before putting this rig into daily driving shape, along with other extensive work but I don't remember reading it needed a new shuttle valve. It's been so long since I read it so I may have missed it or ignored it all together if that's the case. But just to be sure, even with option b completed she can still throw valve codes if there is an issue with them?

 

As near as I understand, yes. You can still have shuttle valve failure with option B. Again, the valve still functions as normal, but the ground just bypasses something to keep it from going wonky. Also, regarding using a new one, they guys at GBR are who told me they always use a new one, and I trust them implicitly, so I take that as gospel.

 

Ok. So looks like I'm going to be swapping shuttle valves. Thank you.

 

If the fault goes away after a key cycle and Option B has been installed it's usually a dirty/corroded ground wire. Or as I've probably mentioned before the insulation on the shuttle valve switches has fallen to bits. If the system has an actual hard fault the fault will not clear with just a key cycle. It would require a scan tool.

 

I will go with Best 4x4. I posted about two weeks ago about random 3 amigos and he pointed out that checking the quality of your ground connection should be first if you have done the Option B mod and have issues. He was right in my case. I just neve got to circle back on my post and report.

 

Option B bypasses a faulty solder connection between the shuttle valve switches and the wiring harness back to the SLABS computer.

I'm a little confused about your statement that the codes you found were for the front-left and right-rear valves. More common would be codes for the wheel speed sensors, not the valves inside the ABS modulator. The connectors for the wheel speed sensors are a common failure point.

But as others have said, I'd also check and clean up the ground for the Option B bypass. Even Josh Salas, the demi-God who came up with Option B, had the Boys from South of the Border come back on his truck due to a faulty ground connection.

No one is swapping shuttle valves. What sometimes get swapped are the shuttle valve switches. But even that doesn't address the shuttle valve switch error code if the failed solder joint is the problem. That is addressed by Option B.

 

Where is the ground connection? The RAVE diagrams I have show it near the hood button. Either that's not NAS or I'm overlooking it.

 

The ground we are talking about here will not be found in RAVE. It's the ground point created when Option B is done.

Josh Salas chose to use the refrigerant line clamp bolt next to the ABS module as the Option B ground. That's what I did (pictured here).