Symptoms Verification: Notes

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban, and 2018 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.

Before using the Symptom tables, perform the following inspections:

Verify the engine control module (ECM) and malfunction indicator lamp (MIL) are operating correctly.
Verify there are no DTCs that are stored.
Verify the scan tool data is within a normal operating range. Refer to Control Module References for scan tool information.
Verify the customer concern.
Perform the Visual/Physical Inspection. The visual/physical inspection is extremely important, and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.