'01 LB7 Check Engine Light Comes on While Switching DSP

[Coojac]

This is also posted on dieselplace.com but only one response thus far. I've got an 01 LB7 running all stock except EFI Live with a DSP5 switch. For whatever reason, in the last few months when I switch from DSP2 to DSP3 or to DSP4, the check engine light comes on within seconds. If you move the switch back to DSP2, DSP1 or Non-DSP, the check engine light goes off. I have tried pulling codes, but nothing comes up. I am thinking the truck is older and has 160k that the injection pump or injectors don't like the high horsepower tunes and the pump may be showing signs of old age? Could the problem be in the EFI Live tunes? Otherwise, I've got nothing. Anyone have any ideas? I really need to get this solved before I end up on the side of the road waiting for a tow truck. Yes, I know I could leave it in DSP2 and call that good, but that defeats the purpose of a 5 position switch and multiple tunes. Need to figure this out. Thank you.

[GMC-2002-Dmax]

Try upgrading the tune file to 15186006 and ditch the 2001 OS.

If you need a copy let me know, I have all the files for Allison, ZF6 and auto or manual transfer case trucks, Federal or CA Emissions.

[Coojac]

Try upgrading the tune file to 15186006 and ditch the 2001 OS.

If you need a copy let me know, I have all the files for Allison, ZF6 and auto or manual transfer case trucks, Federal or CA Emissions.

Thanks. The truck is running OS 01337605 with a calibration of 15063375. If you have a more recent file, I would greatly appreciate it. I clicked on the tab for Upgrade OS, but there is nothing to select.

Thank you.

JC