Testing Procedure

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

1. Record Customer Complaint
   
   Ensure all customer complaints or observations are recorded. Test drive vehicle with customer when necessary for malfunction verification.
2. DLC3 Inspection
   
   Connect the OBD II scan tool or hand-held tester to DLC3. See Figure. If the display indicates a communication fault in the tool, inspect DLC3. See DATA LINK CONNECTOR NO. 3 INSPECTION  under SCAN TOOL PROBLEMS.
3. Retrieve DTCs & Freeze Frame Data
   
   Using Toyota hand-held tester or scan tool, retrieve diagnostic trouble codes (DTC) from engine control module (ECM) and record any freeze frame data (if applicable). See RETRIEVING DIAGNOSTIC TROUBLE CODES  and FREEZE FRAME DATA  .
4. Clear DTCs & Freeze Frame Data
   
   Using Toyota hand-held tester or scan tool, clear DTCs and freeze frame data from ECM. See CLEARING DIAGNOSTIC TROUBLE CODES .
5. Visual Inspection
   
   Inspect all electrical connectors and wiring for suspected circuit or component. Ensure all electrical connections are clean and tight.
6. Check Mode Diagnosis
   
   Set the check mode diagnosis. See TWO-TRIP DETECTION LOGIC .
7. Confirm Symptoms
   
   If the engine does not start, perform steps  9 and  10 first. If a malfunction occurs, go to the next step. If a malfunction does not occur, simulate symptom. Perform road test. Determine if original symptoms still exist, then go to the next step.
8. DTC Check
   
   Check DTC. See SYSTEM OVERVIEW . If DTC is normal, go to the next step. If there is a malfunction code, go to step  11.
9. Basic Inspection
   
   Perform basic inspection. See BASIC INSPECTION . If results are OK, go to the next step. If results are not good, inspect parts, then go to step  13.
10. Determine Symptom
    
    If no DTCs are present and a driveability condition exists, diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.). See SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article. If circuits are OK, inspect parts and go to step  13. If circuits are not good, go to the next step.
11. Diagnose & Repair Diagnostic Trouble Codes
    
    For DTC descriptions, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . Perform appropriate DTC test. See DIAGNOSTIC TESTS . If no DTCs are present and a no start condition exists, proceed to appropriate BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If results are OK, go to step  13. If the results are not good, go to the next step.
12. Intermittent Problem Check
    
    Check for intermittent problems. See INTERMITTENT PROBLEMS CHECK (HAND-HELD TESTER ONLY) .
13. Verification Procedure
    
    Identify problem and make necessary adjustments and repairs. After repairs have been completed, clear all DTCs from ECM. See CLEARING DIAGNOSTIC TROUBLE CODES . Perform road test. Ensure no DTCs exist and all symptoms and/or complaints have been repaired.