FG1 - DTC 1390: Visually Inspect Octane Adjust Connector

Diagnostic Trouble Code (DTC) 1390 indicates OCT ADJ shorting bar is not in or the OCT ADJ circuit is open.

- Key Off.

- Visually inspect in-line connector.

- Is shorting bar removed?

YES -- Go to FG2. FG2 - Check For Modification Decal

NO -- Go to FG4. FG4 - Check Continuity of Octane Adjust Circuit