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Home >> Buick >> 2001 >> Century Limited >> Repair and Diagnosis >> Brakes >> Traction Control >> Anti-Lock Brake System With Traction Control System - DELPHI 7 >> Symptom Tests >> Test G: Scan Tool Does Not Communicate With Class 2 Device (Except "W" Body)

Test G: Scan Tool Does Not Communicate With Class 2 Device (Except "W" Body)

  1. Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK  under DIAGNOSIS & TESTING. After performing diagnostic system check, go to next step.
  2. Turn ignition on, with engine off. Using scan tool, attempt to communicate with any module on the class 2 serial data circuit. If scan tool communicate with any module on the class 2 serial data circuit, go to next step. If scan tool does not communicate with any module in the class 2 serial data circuit, go to step  6.
  3. Using scan tool, select display DTCs function for each module. Record all of the displayed DTCs, DTC status and module which set the DTC. If any DTC recorded is in the range of U1000 to U1255, go to next step. If no DTC are in the U1000 to U1255 range, problem is intermittent. See INTERMITTENTS & POOR CONNECTIONS  under DIAGNOSIS & TESTING.
  4. If DTC U1000 or U1255 is the only DTC displayed, go to DTC U1000 and U1255. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  5. Turn ignition off. Disconnect scan tool from DLC. Check for poor connections at DLC terminals No. 2 and 5. See WIRING DIAGRAMS . Repair as necessary. After repairs, go to step  27. If circuit is okay, go to next step.
  6. Check ground circuit for open in DLC terminal No. 5. Repair as necessary. After repairs, go to step  27. If circuit is okay, go to next step.
  7. Check for poor connections at BCM connectors containing the class 2 serial data communication circuits. Repair as necessary. After repairs, go to step  27. If connections are okay, go to next step.
  8. Remove connector from BCM that contains the class 2 serial data circuit that originates from DLC. Check class 2 serial data circuit for high resistance, short to battery voltage or ground between DLC terminal No. 2 and BCM connector that contains the class 2 serial data circuit that originates from DLC. Repair as necessary. After repairs, go to step  27. If circuits are okay, go to next step.
  9. Reinstall connector on BCM that contains the class 2 serial data circuit that originates from DLC. Disconnect PCM connector containing the class 2 serial data circuit that is connected directly to BCM and not through any other module. Disconnect connector from IRC and IPC that contains the class 2 serial data circuit. See WIRING DIAGRAMS . Install scan tool. Turn ignition on, with engine off. Attempt to communicate with BCM through the class 2 serial data circuit. If scan tool communicate with BCM, go to next step. If scan tool does not communicate with BCM, go to step  15.
  10. Turn ignition off. Reinstall connector that containing the class 2 serial data circuit on IRC. Turn ignition on, with engine off. Using scan tool, attempt to communicate with BCM and IRC through the class 2 serial data circuit. If scan tool communicates with BCM and IRC on the class 2 serial data circuit, go to next step. If scan tool does not communicate with BCM and IRC, go to step  16.
  11. Turn ignition off. Disconnect EBCM harness connector containing the class 2 serial data circuit. Reconnect PCM connector containing the class 2 serial data circuit. Turn ignition on, with engine off. Using scan tool, attempt to communicate with BCM, IRC and PCM through the class 2 serial data circuit. If scan tool communicates with BCM, IRC and PCM on the class 2 serial data circuit, go to next step. If scan tool does not communicate with BCM, IRC and PCM, go to step  17.
  12. Turn ignition off. Disconnect SDM harness connector. Reconnect IPC harness connector. Turn ignition on, with engine off. Using scan tool, attempt to communicate with BCM, IRC, PCM and IPC through the class 2 serial data circuit. If scan tool communicates with BCM, IRC, PCM and IPC on the class 2 serial data circuit, go to next step. If scan tool does not communicate with BCM, IRC, PCM and IPC, go to step  18.
  13. Turn ignition off. Reconnect SDM harness connector. Turn ignition on, with engine off. Using scan tool, attempt to communicate with BCM, IRC, PCM, IPC and SDM through the class 2 serial data circuit. If scan tool, communicates with BCM, IRC, PCM, IPC and SDM on the class 2 serial data circuit, go to next step. If scan tool does not communicate with BCM, IRC, PCM, IPC and SDM, go to next step. If scan tool does not communicate with BCM, IRC, PCM, IPC and SDM, go to step  19.
  14. Turn ignition off. Reconnect EBCM connector that contains the class 2 serial data circuit. Turn ignition on, with engine off. Using scan tool, attempt to communicate with BCM, IRC, PCM, IPC, EBCM and SDM through the class 2 serial data circuit. If scan tool communicates with BCM, IRC, PCM, IPC, EBCM and SDM on the class 2 serial data circuit, go to step  27. If scan tool does not communicates with BCM, IRC, PCM, IPC, EBCM and SDM, go to step  20.
  15. Turn ignition off. Check the class 2 serial data circuit between connector at IRC and connector at BCM for high resistance, short to battery voltage or ground. Check the exclusive class 2 serial data circuit between the connector at PCM and connector at BCM for high resistance, short to battery voltage or ground. Check the exclusive class 2 serial data circuit between connector at IPC and connector at BCM for high resistance, short to battery voltage or ground. Repair as necessary. After repairs, go to step  27. If circuits are okay, go to step  21.
  16. Turn ignition off. Remove connector containing the class 2 serial data circuit from IRC. Remove connector containing the exclusive class 2 serial data circuit for IRC from BCM. Check class 2 serial data circuit between IRC and BCM for high resistance, short to battery voltage or ground, or for poor connections. Repair as necessary. After repairs, go to step  27. If circuits are okay, go to step  25.
  17. Turn ignition off. Remove connector containing class 2 serial data circuit from PCM. Check the exclusive class 2 serial data circuit between PCM, EBCM and BCM for high resistance, short to battery voltage or ground. Check for poor connections at connector on PCM that contains the class 2 serial data circuit. Repair as necessary. After repairs, go to step  27. If circuits and connections are okay, go to step  22.
  18. Turn ignition off. Disconnect connector that contains the exclusive class 2 serial data circuit between IPC and BCM from BCM. Disconnect IPC connector. Check the exclusive class 2 serial data circuit between IPC connector, SDM and BCM for high resistance, short to battery voltage or ground. Check for poor connections at IPC harness connector. Repair as necessary. After repairs, go to step  27. If circuits and connectors are okay, go to step  23.
  19. Turn ignition off. Disconnect IPC and SDM harness connectors. Check the exclusive class 2 serial data circuit between IPC and SDM connector for high resistance, short to battery voltage or ground. Check the exclusive class 2 serial data circuit between EBCM and SDM connector for high resistance, short to battery voltage or Ground. Check for poor connections at SDM and IPC harness connectors. Repair as necessary. After repairs, go to step  27. If circuits and connections are okay, go to step  24.
  20. Turn ignition off. Disconnect SDM harness connector. Disconnect connector that contains the class 2 serial data circuit from PCM and EBCM. Check for poor connections at SDM, EBCM and PCM harness connectors. Repair as necessary. After repairs, go to step  27. If connections are okay, go to step  26.
  21. Replace BCM. After replacing BCM, go to step  27.
  22. Replace PCM. After replacing PCM, go to step  27.
  23. Replace IPC. After replacing IPC, go to step  27.
  24. Replace SDM. After replacing SDM, go to step  27.
  25. Replace IRC. After replacing IRC, go to step  27.
  26. Replace EBCM. After replacing EBCM, go to next step.
  27. Reconnect all disconnected modules and connectors. Turn on, with engine off. Scan tool may require a power up reset before communication will occur due to a short on class 2 serial data circuit. Turn off or disconnect scan tool before displaying DTCs. Wait for 10 seconds. Using scan tool, attempt to communicate with each module on class 2 serial data circuit. If scan tool communicates with each module on class 2 serial data circuit, go to next step. If scan tool does not communicate with each module on class 2 serial data circuit, go to step  2.
  28. Using scan tool, check and record DTCs. If any DTCs are present, diagnose affected DTCs. After diagnosing all DTCs, clear DTCs using scan tool.
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