Diagnosing Intermittents

Diagnosing intermittent conditions can be difficult. The conditions that set the DTC set may not be present. This does not mean that the problem is fixed, it simply means that the problem intermittently occurs. The problem may return in the future. The improper installation of aftermarket add-on components or equipment may induce an intermittent while in use. Refer to Aftermarket (ADD-ON) Electrical And Vacuum Equipment. The only way to diagnose an intermittent condition is to gather information from the time when the DTC was set. This can be done in two ways; through snapshot data and driver observations.