2019 Silverado. 5 miles on it.
Check engine light on.
8 codes for 4 cylinders deactivation solenoids.
View attachment 169096
According to chart, I need to disconnect solenoid jumper harness and test circuits there.
Bbuuutt, I need to remove the intake manifold to get to said connector.
And to get the ECM to command the solenoids on, it requires the engine running.
View attachment 169097
Plus, when I have it running, it boots me out of it, stating the ignition voltage is too high..
So, I winged it, ohmed all solenoids at the ECM connector, checked for short to B+, ground, etc.
Had to call the omnipotent General anyhow because the ECM is on restriction.
Guy at tech assistance laughed when I explained how their diagnostic chart works.
At least he gave me an authorization number to get a module..
View attachment 169098