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PCM or performing resistance tests. 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, display and record Diagnostic Trouble DTCs (DTCs). See ENTERING ON-BOARD DIAGNOSTICS under SELF-DIAGNOSTIC SYSTEM. If scan tool is blank, see SCAN TOOL WILL NOT COMMUNICATE. If no DTCs are displayed, see H - TESTS W/O CODES 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. SCAN TOOL WILL NOT COMMUNICATE NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For circuit and wire color identification, see L - WIRING DIAGRAMS article. 1) Using DVOM, check voltage between Data Link Connector (DLC) terminal No. 16 and chassis ground. If battery voltage does not exist, check and repair junction connectors and wiring harness between DLC and power supply. 2) If battery voltage exists, check for continuity between DLC terminal No. 4 and chassis ground, and between DLC terminal No. 5 and chassis ground. If continuity does not exist, check and repair wiring harness between DLC and chassis ground. If continuity exists, go to next step. 3) Try a different scan tool adapter cable. If scan tool does not communicate, try scan tool on a known-good vehicle. If scan tool still does not communicate, replace scan tool. INTERMITTENT DTCS This procedure applies if you have been sent here from diagnostic tests and have just attempted to simulate the condition that initially set DTC. The following additional checks may assist in identifying a possible intermittent problem: * Visually inspect related wiring harness connectors for broken, bent, pushed out or corroded terminals. * Visually inspect related wiring harness for chafed, pierced or partially broken wires. * Check all pertinent technical service bulletins. DTC P0100: VOLUME AIRFLOW (VAF) SENSOR CIRCUIT FAILURE NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For circuit and wire color identification, see L - WIRING DIAGRAMS article. NOTE: Procedures are provided by manufacturer for component testing using an engine analyzer with oscilloscope capability. Refer to manufacturer’s operation manual for instructions in use of oscilloscope. 1) If using scan tool, go to step 3). Disconnect VAF sensor connector. Install Test Harness (MB991348) between VAF sensor and connector. Using engine analyzer with oscilloscope capability, connect |