Diagnostic Tests: Notes

CAUTION: Ensure ignition switch is in OFF position when performing resistance tests.

NOTE: PCM diagnostic memory is retained by direct power supply from battery. Memory is not erased by turning off ignition, but it will be erased if battery or PCM is disconnected.

NOTE: Perform all resistance and voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm impedance, unless stated otherwise in test procedures.

Using scan tool or MIL, display and record Diagnostic Trouble Codes (DTCs). See ENTERING ON-BOARD DIAGNOSTICS under SELF-DIAGNOSTIC SYSTEM. If no DTCs are displayed, see TESTS W/O CODES - NON-TURBO article.

Clear DTCs. See CLEARING DTCS under SELF-DIAGNOSTIC SYSTEM. Road test vehicle (if necessary) and attempt to duplicate conditions that caused original complaint. Recheck for DTCs. If no DTCs are displayed, go to INTERMITTENT DTCS . If one or more DTCs are displayed, repair DTCs in order starting with lowest numbered DTC. Clear DTCs after each repair. Recheck for DTCs to confirm repair.