Circuit/System Verification
WARNING: This page is about a different car, the 2011 GMC Yukon, 2011 Chevrolet Tahoe, and 2011 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Diagnose and repair any communication DTCs prior to performing this testing.
If the DTC is set, program the K20 ECM. If the DTC resets, replace the K20 ECM.