I decided to start a new post for this situation since it's very specific. But background here on my '7060 to '7427 conversion if it's helpful. Still lots to resolve on the conversion, but I think the most important thing right now is to get the KS issue resolved.

So the weird thing about the code 43 I'm getting (in TunerPro and SES illuminates) is that it will set either immediately after starting the engine OR it will set after about 30 seconds of key on, engine NOT running. For both tests I'm sure the code is cleared by unplugging both ECM connectors for a minute and restarting TunerPro to clear the flag there. And both tests are consistent. Is it strange that the flag will set without the engine running? Stuff I've seen says that it does not do its diagnostic until after engine is running. Does that point to a possible ECM or Memcal issue? I will go through the FSM diagnostic procedure on the KS circuit, but wanted to check here to see if maybe that's not necessary based on the above observations.