Symptom Troubleshooting (Engine Control System L3): Foreword

When the customer reports a vehicle malfunction, check the malfunction indicator lamp (MIL) indication and diagnostic trouble code (DTC), then diagnose the malfunction according to the following flowchart:
- If a DTC exists, diagnose the applicable DTC inspection. (See DTC TABLE .)
- If no DTC exists and the MIL does not illuminate or flash, diagnose the applicable symptom troubleshooting. (See QUICK DIAGNOSTIC CHART .)
  
  Fig 1: Diagnosis Flowchart
  Courtesy of MAZDA MOTORS CORP.