Initial Inspection and Diagnostic Overview

1. Verify the customer concern is with the evaporative emission (EVAP) system.




2. Visually inspect for the following obvious signs of mechanical damage.

3. If the concern remains after the inspection, connect the NGS Tester to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the NGS Tester menu. If the NGS Tester does not communicate with the vehicle:
- check that the program card is correctly installed.
- check the connections to the vehicle.
- check the ignition switch position.

4. If the NGS Tester still does not communicate with the vehicle, refer to the NGS Tester manual.

5. Carry out the DATA LINK DIAGNOSTICS test. If the NGS Tester responds with:
- CKT914, CKT915 or CKT7O = ALL ECUS NO RESP/NOT EQUIP, refer to COMMUNICATIONS NETWORK
- NO RESP/NOT EQUIP for PCM, refer to the Powertrain Control/Emissions Diagnosis Manual.
- SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out the PCM KOEO self-test.

6. If the DTCs retrieved are related to the concern, go to the PCM Diagnostic Trouble Code (DTC) Index to continue diagnostics.
7. If the concern remains after the inspection, determine the symptom and proceed to the Symptom Chart.