Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and to store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
2. If a vent solenoid or EVAP Canister Purge Valve electrical malfunction is present, the purge system will not operate correctly.
3. Checks the fuel tank pressure sensor at ambient pressure.
4. Determines whether or not the EVAP system is sealed sufficiently to be pressurized. If not, the large leak must be located and corrected before continuing with diagnosis.
5. Verifies that the fuel tank pressure sensor accurately reacts to EVAP system pressure changes.
6. Ensures that sufficient source vacuum is present at the EVAP Canister Purge Valve.
7. Checks for a stuck, closed EVAP Canister Purge Valve.
8. Insures proper system integrity.