GM Scanner found code CO660 how do you fix it?
Find where the compressor assembly is on your vehicle. Unplug
the connector with all wires. Set your DVOM to ohms and check the
resistance on the compressor side of the connector of the light
blue wire and the gray wire..... it should be 18-45ohms. That is
the exhaust valve solenoid which the computer throws code CO660
when it's bad. There's no repair for it, just replace the whole
compressor assembly.
if you diagnose the GM by GM MDI, you can repair it or reset by
some obd2 code scanner from vipprogrammer.com