I have a 2003 Land Rover Discovery 2. I just turned over 100k miles, having purchased it with 94k miles. I took my truck to Tim Scully's Scully Offroad in Rancho Cordova for a whole bunch of fun upgrades. Most of these upgrades are irrelevant to this problem, but others are clearly connected somehow. Just giving total context in case I overlooked something.

1. new heavy duty steering rod
2. ome steering damper
3. replaced the stock 2003 center diff with a locking center diff
4. heavy duty drive shafts, front and rear, from GBR Utah
5. new front and rear differentials with Eaton E-lockers, manufactured by GBR Utah
6. heavy duty axles, front and rear
7. 3" lift with 1" spacers + new springs + new shocks
8. Extended brake line in the rear to facilitate the lift
9. new terrafirma wheels, BFG all-terrain tires
10. Replaced all four hubs and ABS sensors.
    Per Tim, when installing the axles, an ABS fault came on. He got ABS faults for 3 out of 4 sensors. He opted to replace all four hubs, which come with ABS sensors.

That's all the work. Now, here's the narrative of the errors.

1. He tested the truck a whole bunch this Thursday and the three amigos did not come on. I picked up the truck yesterday, Friday. No three amigos.
2. After I took the truck from him, I hit a speed bump 10 miles from the shop, three amigos came on. Turned the car off and back on to run the code reader, no code found.
3. Turned the car off in the same spot, walked into the Starbucks to get food and call Tim about the code. Go back to the truck, turn it on, three amigos was not there. Can't remember if it was up and went away a second after the truck was running, or if it just wasn't there when I started it. I think it's the former but memory is foggy.
4. Drove it home, happy the code went away. Hit a bump on the highway, three amigos came back on.

Appears to be triggered by hitting bumps.

I drove straight to my local SF shop (11th street auto). He ran a big code reader and received this code. He – Land Rover mechanic for over a decade – nor Tim – Land Rover mechanic for over a decade – knew what this code is. They both hadn't seen this code before. What is it and how do I fix it?

The code in the photo is, "Ecu ground or reference ground fault. Fault present"

 

Best to post this D2-related question in the D2 section of the forum. You'll get more eyes on it there.

 

This seems too obvious, but maybe a wire was pulled loose somewhere during the installs and is shorting. I got an ECU warning once due to a faulty TPMS sensor reading. But that wasn't on an MB.