Diagnostic Procedure
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Check for applicable service bulletins before proceeding with this test. Perform this test only if there is a driveability complaint or if you have been directed to this table from another section in the service information.
NOTE:
Do not turn the ignition off when performing this diagnostic procedure. Do not clear the DTCs unless instructed by this diagnostic procedure.
- Turn ignition on, engine off. Does the scan tool turn on? If so, go to next step. If not, diagnose scan tool concern. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
- Is the MIL on? If so, go to next step. If not, diagnose MIL concern. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
- Attempt to establish communication with the TCM. Does the scan tool communicate with the TCM? If so, go to next step. If not, diagnose scan tool concern. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.NOTE: Diagnostic Trouble Codes (DTC), engine performance, and transmission default actions can greatly affect the transmission performance. Ensure that these items are not the cause of a transmission concern.
- Use the scan tool CAPTURE INFO function to save or capture (store information) any DTC information. Are there any DTCs present? If so, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If not, see SYMPTOM DIAGNOSIS under TROUBLE SHOOTING.