Diagnostic Aids

Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To look at the sensor signal under vacuum conditions, use snapshot and the purge/seal function to capture data while commanding purge to 20 percent, then plot the data to look for non-linear sensor operation. A similar inspection can be done for the pressure side of the sensor range by applying pressure with the J 41413-200  Evaporative Emissions System Tester (EEST) while taking a snapshot. See Special Tools . DO NOT exceed 5 inches H2O when applying pressure.