I suggested the battery disconnect to ensure any old stored codes are causing the issue , my P0128 code showed up pretty quickly.

 

What I am getting at is MOST codes will clear themselves once the condition that set them is remedied. So, if you replace the VVT solenoid and then clear the codes, ALL codes will be cleared and it may take a while before you can get a reading. Any stored or historic codes are now gone.

Yes, some codes will pop up on the first occurrence, but some take three. Some will clear themselves after 1 clean cycle some take several.

One of the other possible causes of a P0010 is a damaged wiring harness, you wouldn't be wasting your time inspecting for burned or chafed wires. But, you presumably did that while you were playing with the VOM.

 

I think that depending on the OBD II code that has been set, it takes between 25 and 50 "Cycles" for a stored code to Self-Clear.

GM's definition of a Cycle is an engine start, X minutes of run time, then an engine shutdown.

What I can't find right now is the minimum of run time time in a Cycle, hence the hazy inclusion of "X minutes" into the equation.

I think a few years back, we came to the conclusion of a simple "Loose Cap/Bad Fuel Cap" code taking 50 cycles to self clear.

 

Hence my suggestion, I agree with Don, and Mike has a point, to impatient to wait for cycles and unknown time frames .