Turning off the Auxiliary powertrain control module

[donaldtfreeman]

I have a 2009 E450 that I'm trying to do some diagnostics on. When I attempt the Key On Engine Running test, the engine will momentarily stumble and the display will say that the test can't be completed because of the APCM. It says that the APCM must be disabled for the test to continue. This happens with both Forscan and a Snap-on analyzer.
This vehicle doesn't have the adjustable idle control box. You engage the parking brake and it fast idles.
How do I disable this so I can do the diagnostics?
Thanks