Diagnostic Aids
WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
Verify the smooth and consistent mechanical operation of each part of the door latch system prior to performing extensive electrical diagnostics
Any door that does not function smoothly or consistently, refer to Door Will Not Open/Close, Door Binding, or Locks, Handles, or Cylinders Do Not Function .