I am still repairing a 2008 GMC Yukon Denali, purchased broken, customer claimed blown head gasket and other issues so I got it inexpensively but in need of TLC. Engine fully repaired, all fluids in the car changed, Oil Pan gasket and Oil pump Oring replaced. Oil pump removed and by pass spring pressure increased for better oil pressure. New oil pump by pass valve in pan. New Dash, New struts in rear and new rear actuator to control the electric rear hatch. All Good. Engine runs great. 30+ idle hot oil pressure, 55 at cruse speed.
Passed smog check and all good as far as engine.
Problems with rear suspension and code in system for C0-660-06. problem with exhaust valve in compressor? Found compressor would not function even with direct power supplied. Installed brand new AC Delco compressor, the original code of C0660-06 is now gone when scanning the system but new code of C0-711-00 has shown up? Compressor works, scan tool allows me to test the compressor, look at all 4 wheel sensors, all show the level adjustment is working, I checked all the wires thinking I had messed up and damaged one while installing the compressor? All seemed good? Looking at the scan tool the compressor shows voltage at the exhaust valve and in line pressure. Voltage showed 4.98V? Max if 5v and normal should be between .15v and 5v? No matter what I only see the constant voltage and pressure?
I removed the lines, no change? I took the exhaust valve off my OLD compressor that was locked up and installed the old valve on the new compressor. The Co711-00 code will now clear and has not come back?
I installed 2 new rear shocks as my old ones would not hold air. No surprise. Used Arnott AS 2708's for my Z55 system. All good now but still looking forward to first test drive. Thought I would pass along the results of the code chasing. I wasted many hours tracing wires due to the bad new AC Delco compressor. Last time I changed one of these I used the Dorman unit and it worked flawlessly right away.
