Diagnostic Procedure

Turn ignition on. Using scan tool, read DTCs. If DTC 91 or 92 is set as history or current DTC, go to appropriate test and repair as needed. If DTC 91 or 92 is not set as history or current DTC, use enhanced diagnostic function of scan tool. Verify malfunction frequency was low. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under DIAGNOSIS & TESTING.