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HOMESERVICE MANUALSCHEVROLET2001CAVALIER LS, 2.4 TREPAIR AND DIAGNOSISBRAKESTRACTION CONTROLANTI-LOCK BRAKE SYSTEM WITH TRACTION CONTROL SYSTEM - DELPHI 7SYMPTOM TESTSTEST H: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE ("W" BODY)
2001 Chevrolet Cavalier LS, 2.4 T

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

2001 Chevrolet Cavalier LS, 2.4 TSECTION Test H: Scan Tool Does Not Communicate With Class 2 Device ("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 each module on the class 2 serial data circuit. If scan tool communicates with any module on the class 2 serial data circuit, go to next step. If scan tool does not communicate with any module on the class 2 serial data circuit, go to step  5.
  3. Using scan tool, select display DTCs function for each module. Record all of the displayed DTCs, DTC status and the module which set the DTC. If any DTCs are in the range of U1000 to U1255, go to next step. If DTCs are not in the range of U1000 to U1255, ensure BCM is connected to class 2 serial data circuit.
  4. If DTC U1000 or U1255 is the only DTCs displayed, diagnose affected DTC. If DTC U1000 or U1255 is not set, go to DTC U1001-U1254. 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. If circuit is okay, go to next step.
  6. Check for open in DLC ground circuit terminal No. 5. Repair as necessary. If circuit is okay, go to next step.
  7. Check for poor connections at scan tool connector. Repair as necessary. If connector is okay, go to next step.
  8. Check class 2 serial data circuit for an open or a short between DLC and star connector. Repair as necessary. After repairs, go to next step.
  9. Connect a jumper wire to DLC terminal of star connector. Connect the other end of jumper wire to BCM terminal of star connector. Turn ignition on, with engine off. Using scan tool, attempt to communicate with BCM. If scan tool communicates with BCM, go to step  11. If scan tool does not communicate with BCM, go to next step.
  10. Turn ignition off. Disconnect BCM harness connector. Check class 2 serial data circuit between star connector and BCM for a short to ground or a short to voltage. Turn ignition on, with engine off when testing for short to voltage. Repair as necessary. After repairs, go to step  25. If circuit is okay, go to step  23.
  11. Leave jumper wire connected to DLC terminal and to BCM terminal of star connector. Connect another jumper wire to jumper wire connected to DLC terminal of star connector. Connect the other end of jumper wire to PCM terminal of star connector. Turn ignition on, with engine off. Using scan tool, attempt to communicate with PCM. If scan tool communicates with PCM, go to step  13. If scan tool does not communicate with PCM, go to next step.
  12. Turn ignition off. Disconnect PCM harness connector. Check class 2 serial data circuit between star connector and PCM for a short to ground or a short to voltage. Turn ignition on, with engine off when testing for a short to voltage. Repair as necessary. After repairs, go to step  25. If circuit is okay, go to step  23.
  13. Disconnect jumper wire from PCM terminal of star connector. Connect jumper wire to EBCM terminal of star connector. Turn ignition on, with engine off. Using scan tool, attempt to communicate with EBCM. If scan tool communicates with EBCM, go to step  15. If scan tool does not communicate with EBCM, go to next step.
  14. Turn ignition off. Disconnect EBCM harness connector. Check class 2 serial data circuit between star connector and EBCM for a short to ground or a short to voltage. Turn ignition on, with engine off when testing for a short to voltage. Repair as necessary. After repairs, go to step  25. If circuit is okay, go to step  23.
  15. Disconnect jumper wire from EBCM terminal of star connector. Connect jumper wire to SDM terminal of star connector. Turn ignition on, with engine off. Using scan tool, attempt to communicate with SDM. If scan tool communicates with SDM, go to step  17. If scan tool does not communicate with SDM, go to next step.
  16. Turn ignition off. Disconnect SDM harness connector. Check class 2 serial data circuit between star connector and SDM for a short to ground or a short to voltage. Turn ignition on, with engine off when testing for short to voltage. Repair as necessary. After repairs, go to step  25. If circuit is okay, go to step  23.
  17. Disconnect jumper wire from SDM terminal of star connector. Connect jumper wire to IPC terminal of star connector. Turn ignition on, with engine off. Using scan tool, attempt to communicate with IPC. If scan tool communicates with IPC, go to step  19. If scan tool does not communicate with IPC, go to next step.
  18. Turn ignition off. Disconnect IPC. Check class 2 serial data circuit between star connector and IPC for a short to ground or a short to voltage. Turn ignition on, with engine off when testing for short to voltage. Repair as necessary. After repairs, go to step  25. If circuit is okay, go to step  23.
  19. Disconnect jumper wire from IPC terminal of star connector. Connect jumper wire to HVAC control module terminal of star connector. Turn ignition on, with engine off. Using scan tool, attempt to communicate with HVAC control module. If scan tool communicates with HVAC control module, go to step  21. If HVAC control module does not communicate with scan tool, go to next step.
  20. Turn ignition off. Disconnect HVAC control module harness connector. Check class 2 serial data circuit between star connector and HVAC control module for short to ground or short to voltage. Turn ignition on, with engine off when testing for short to voltage. Repair as necessary. After repairs, go to step  25. If circuit is okay, go to step  23.
  21. Disconnect jumper wire from HVAC control module terminal of star connector. Connect jumper wire to Vehicle Interface Unit (VIU) terminal of star connector. Turn ignition on, with engine off. Using scan tool, attempt to communicate with VIU. If scan tool communicates with VIU, go to step  25. If scan tool does not communicate with VIU, go to next step.
  22. Turn ignition off. Disconnect IPC harness connector. Check class 2 serial data circuit between star connector and IPC for short to ground or short to voltage. Turn ignition on, with engine off when testing for short to voltage. Repair as necessary. After repairs, go to step  25. If circuit is okay, go to next step.
  23. Check for poor connection at class 2 serial data circuit of module that is not communicating. Repair as necessary. After repairs, go to step  25. If connection is okay, go to next step.
  24. Replace module that is not communicating. After replacing affected module, go to next step.
  25. Reconnect all disconnected modules. Reconnect any other disconnected connectors. Install scan tool. Turn ignition on, with engine off. Wait 10 seconds. Scan tool may require a power up reset before communication will occur if there was a short on the class 2 serial data circuit. Turn off or disconnect scan tool prior to performing this test. Using scan tool, select display DTCs function for each module. Record all of displayed DTCs and DTC status. If any recorded DTCs are current DTCs that begin with "U", go to step  27. If recorded DTCs does not begin with "U", go to next step.
  26. If any recorded DTCs do not begin with a "U", go to next step. If no DTCs are recorded, clear DTCs using scan tool.
  27. Diagnose affected DTCs. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. After repairs, go to next step. Clear all DTCs using scan tool.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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