Low load is everything below 5.4 inches of vacuum (set in the top right field), when it's in low load, it's shooting for 14.7 lambda but i guess it means afr (set in the top left field). Anything above 5.4 inches of vacuum (top right field), but below 1 or psi (bottom right field) is considered medium load and will shoot for whatever lambda/afr is in the middle left field. Anything above 1 or 2 psi, (set in bottom right field) is considered high load and will shoot for whatever lambda/afr is set