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PCI Bus Communication Failure

NOTE: Verify modules vehicle is equipped with before attempting communication.
  1. Connect Diagnostic Junction Port Tester (8339) between scan tool and diagnostic junction port. See Figure. Using scan tool, select JUNCTION PORT TOOL then PCI BUS MODULE SCAN. Follow on-screen instructions on scan tool. If no modules communicate with scan tool, go to next step. If scan tool communicates with any modules, go to appropriate testing procedure for module(s) that did not communicate with scan tool. See SYMPTOM IDENTIFICATION  table under RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Perform BODY VERIFICATION TEST  under VERIFICATION TESTS.
  2. Using DVOM, measure resistance of Yellow/Violet wire between Data Link Connector (DLC) terminal No. 2 and diagnostic junction port connector terminal No. 9. See Figure. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open in Yellow/Violet wire between DLC and diagnostic junction port. Perform BODY VERIFICATION TEST  under VERIFICATION TESTS.
  3. Using scan tool, select JUNCTION PORT TOOL then PCI BUS CONTROL MODE. Follow on-screen instructions on scan tool. Perform test for each pin equipped with PCI bus circuit. If scan tool displays NO MODULES RESPONDING for any pin after performing scan, go to next step. If scan tool does not display NO MODULES RESPONDING, check for short to voltage in Yellow/Violet wire between DLC and diagnostic junction port. Perform BODY VERIFICATION TEST  under VERIFICATION TESTS.
  4. Disconnect diagnostic junction port tester from scan tool only. Turn ignition on. Using DVOM, measure voltage of PCI bus circuit on diagnostic junction port tester that corresponds with pin that scan tool displayed NO MODULES RESPONDING at. If voltage is greater than 7 volts and steady, go to next step. If voltage is not greater than 7 volts or not steady, go to step  6.
  5. With DVOM connected to PCI circuit(s) that measured greater than 7 volts and steady, turn ignition off and disconnect corresponding module connector for each circuit. Turn ignition on. If problem occurred at pins No. 1 or 2 of diagnostic junction port tester, monitor DVOM reading while disconnecting each module connector one at a time. If voltage is still greater than 7 volts and steady, repair short to voltage in PCI bus circuit. Perform BODY VERIFICATION TEST  under VERIFICATION TESTS. If voltage is no longer greater than 7 volts and steady, replace corresponding module. Perform BODY VERIFICATION TEST  under VERIFICATION TESTS.
  6. Turn ignition off. Disconnect negative battery cable. Using DVOM, measure resistance between ground and diagnostic junction port tester terminal pin corresponding with module that displays NO MODULES RESPONDING. If resistance is less than 100 ohms, go to next step. If resistance is greater than 100 ohms, go to step  8.
  7. With DVOM connected to PCI circuit(s) that measured less than 100 ohms, disconnect corresponding module connector for each circuit. If problem occurred at pins No. 1 or 2 of diagnostic junction port tester, monitor DVOM reading while disconnecting each module connector one at a time. If resistance is greater than 100 ohms, repair short to ground in PCI bus circuit. Perform BODY VERIFICATION TEST  under VERIFICATION TESTS. If resistance is less than 100 ohms, replace corresponding module. Perform BODY VERIFICATION TEST  under VERIFICATION TESTS.
  8. Turn ignition off. Check PCI bus circuit for poor connections, faulty terminals, pinched wires or faulty insulation and repair as necessary. If circuits are okay, test is complete. Perform BODY VERIFICATION TEST  under VERIFICATION TESTS.
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