No Response From Air Bag Control Module
WARNING:
When reconnecting air bag system components, turn ignition off, disconnect negative battery cable and wait 2 minutes before proceeding with test procedure.
NOTE:
Ensure PCI bus communication between other modules exists before proceeding. If PCI bus module communication does not exist between other modules, go to appropriate system test. See SYMPTOM IDENTIFICATION
table under RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM.
- Disconnect Air Bag Control Module (ACM) connector. ACM is located under center console. Using DVOM, measure resistance between ACM connector terminal No. 4 (Black/Orange wire) and ground. See Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open in Black/Orange wire between ACM and ground. Perform AIR BAG CONTROL MODULE VERIFICATION TEST under VERIFICATION TESTS.
- Use Scope Input Cable (CH7058), Cable-To-Probe Adapter (CH7062) and Red and Black test probes. Connect scope input cable to channel one connector on scan tool. Attach Red and Black test probes and cable-to-probe adapter to scope input cable. Select scan tool STANDALONE function. Select LAB SCOPE. Select LIVE. Select 12 VOLT SQUARE WAVE. Press F2 for scope display. Press F2 and use down arrow to select voltage range to 20 volts. Press F2 after selecting 20 volts. Connect Black test probe lead to ground and Red test probe lead to ACM connector terminal No. 21 (Yellow/Violet/Orange wire). Turn ignition on. Observe voltage readings on scan tool. If reading pulses from zero to approximately 7.5 volts, go to next step. If reading is steady at zero volts, repair PCI bus circuit (Yellow/Violet/Orange wire) between ACM and diagnostic junction port. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Perform AIR BAG CONTROL MODULE VERIFICATION TEST under VERIFICATION TESTS.
- Replace ACM. See AIR BAG CONTROL MODULE under REMOVAL & INSTALLATION. Perform AIR BAG CONTROL MODULE VERIFICATION TEST under VERIFICATION TESTS.