Symptom Duplication

• If you can duplicate the symptom, compare it to a known-good vehicle. If you can duplicate the symptom in the known-good vehicle, then it is a characteristic of the system.

  A known-good vehicle is another vehicle of the same year and model that has the same software version installed.

• When the symptom can be duplicated, follow the self-diagnostic procedures, and the appropriate troubleshooting procedures.
• When the symptom does not reappear, or only reappears intermittently, ask the customer about the conditions when the symptom occurred.
• Always ask the customer to demonstrate the problem.
• Try to establish possible user error, or a misunderstanding of the system.
  • Try to establish if outside interference may have been the cause.
  • Try to duplicate the symptom under the same conditions that the customer experienced.
  • Vibration, temperature extremes, and moisture (dew, humidity) are factors that are difficult to duplicate.
  • Inspect the vehicle for after-market electronic devices (vehicle locators, radar detectors amps, etc.) that may be hidden.

When troubleshooting navigation system problems, ensure that the known-good vehicle is the same software version year and model as the vehicle being serviced. Mixing incompatible navigation DVDs or other system components can delay the troubleshooting process by causing side effects unrelated to the original problem.