Symptom Troubleshooting Versus DTC Troubleshooting

Some symptoms will not set DTCs or cause the D indicator to blink. If the MIL has been reported ON or the D indicator has been blinking, check for DTCs. If the vehicle has an abnormal symptom, and there are no DTCs stored, do the symptom troubleshooting. Check the list of probable cause (s) for the symptom, until you find the problem.