EGR test result explanation, code P0404

Performed all EGR tests. Still getting p0404.
Same test results on three different units-2 used, 1
brand new. Results as follows, (no carbon problems, already checked all that).
Solenoid -good (9 volts battery test) and resistance within spec.
5 volts reference wire good 5 volts (multi-meter black to ground red to wire d KOEO) which is correct.
Pintle Position Sensor? Manual says should read.6 to.9 volts but I am getting 4.96 volts. I cannot seem to find any information on what that reading means. I know a high read there means valve could be stuck open but I get that reading on the brand new one as well. (This test was KOEO red lead to wire c and black to ground)
The ground test also gave a reading that I cannot find any information about.
Ground test- (KOEO red lead to battery positive black lead to wire a) manual says I should read 10 volts to 12 volts here but I am getting 7.33 volts. I need to know what to look for next. I am at wits end.