Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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 scan tool to Data Link Connector No. 3. See Figure. Retrieve DTCS and record any freeze frame data (if applicable). See RETRIEVING DIAGNOSTIC TROUBLE CODES . - Clear Trouble Codes
Clear DTCs and freeze frame data. See CLEARING DIAGNOSTIC TROUBLE CODES . - 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 DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES . - Diagnose & Repair Diagnostic Trouble Codes
Perform appropriate diagnosis and repair procedures under DIAGNOSTIC TESTS as necessary. For DTC descriptions, see DIAGNOSTIC TROUBLE CODE DEFINITIONS table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If no DTCs are present, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.). - Verification Procedure
After repairs have been completed, clear all DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES . Perform road test. Ensure no DTCs are present and all symptoms and/or complaints have been repaired.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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