[speedygonzales]

You got me there. I just checked the shop manual and it does not mention anything other than the normal bleeding at each wheel. Nothing else. It only mentions the pressure modulator valve if it's been replaced or if you suspect is has air in it.

The antilock bleeding procedure never mentions to open anything other than the bleeders at each wheel. It mentions to use the GM scan tool to run the automated bleed procedure. Then go back and do each wheel by hand.

So it doesn't look like you're gona be able to do any ABS bleeding. Just do the normal method and you're done.