Testing Procedure

To ensure correct diagnosis and repair, testing should be done in the following sequence:

• Record Customer Complaint  - Ensure all customer complaints or observations are recorded. Test drive vehicle with customer when necessary for malfunction verification.
• Retrieve Diagnostic Trouble Codes  - Connect appropriate OBD-II scan tool. Retrieve codes and record any freeze-frame data. See RETRIEVING DIAGNOSTIC TROUBLE CODES .
• Clear Trouble Codes  - Clear codes using scan tool. See CLEARING DIAGNOSTIC TROUBLE CODES .
• Perform Visual Inspection  - Inspect all connectors of suspect circuit or component. Ensure all connections are clean and tight.
• Confirm Symptoms & Trouble Codes  - Perform road test. Determine if original symptoms are still present. Retrieve codes.
• Diagnose & Repair Diagnostic Trouble Codes  - Perform diagnosis and repair procedures as needed. See appropriate tests in this article. If no codes are present, proceed to the TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).
• Verification Procedure  - After repairs have been completed, clear all diagnostic trouble codes. Refer to CLEARING DIAGNOSTIC TROUBLE CODES . Perform road test. Ensure no codes are present and all symptoms and/or complaints have been repaired.