Grim Reaper

If you have disabled your CPP, you may have found that Highway Mode Fuel may not work. There is a parameter at $82E6 to change the minimum CPP DC% which is tested in the Highway Mode Fuel qualification but even if you set it to 0, it may not work.

This is what a friend of mine has found with his SD 7730 (no EGR, no CPP). I have looked at the code and noticed that the test for the minimum CPP DC% is a "Lower than or Same". Since the value from the CPP will be zero, the 0 Mimimum CPP DC% will meet the "same" test and cause it jump out of the routine.

If you change the location C86E from a $23 to a $25 this will make the test become a "Less than" only test and make this minimum value qualify to work.

My friend will testing this on Saturday, so I will be able to confirm the "fix". But if any you a running SD without a CPP and want to get Highway Mode Fuel to work, change location $C86E (or $486E if you edit the memory directly with Pocket Programmer's Window version) from $23 to $25.

Grim Reaper

I just heard from my friend that tried this new code and it works. So if you have disabled the Charcoal Canister Purge, then the fix above will allow you to run Highway Mode Fuel with no CCP working.