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Test B: Scan Tool Does Not Communicate With Class 2 Device: Testing

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Chevrolet Cavalier, 2001 Pontiac Sunfire, and 2001 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect scan tool to Data Link Connector (DLC). DLC is located at lower left side of instrument panel, near steering column. If scan tool powers up, go to next step. If scan tool does not power up, go to TEST A: SCAN TOOL DOES NOT POWER UP  .
    2. NOTE: If using Tech 2 scan tool, obtain information using CLASS 2 MESSAGE MONITOR feature.
  2. Turn ignition switch to RUN position. Attempt to communicate with each module on class 2 serial data circuit. If scan tool communicates with one or more modules, go to next step. If scan tool does not communicate with any module, go to step  6 .
  3. Using scan tool, select DISPLAY DTCs function. Retrieve DTCs for each module. Record DTCs, DTC status and which module set DTC(s). If any DTCs between DTC U1000 and U1255 are retrieved, go to next step. If no DTCs between DTC U1000 and U1255 are retrieved, concern may be intermittent. Check class 2 serial data circuit(s) while wiggling wiring and connectors. This can often cause malfunction to appear.
  4. If DTCs U1000 or U1255 are only DTCs retrieved, go to DTC U1000 & U1255: CLASS 2 COMMUNICATION MALFUNCTION  under DIAGNOSTIC TESTS. If DTCs U1000 or U1255 are not only DTCs set, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  .
  5. Turn ignition switch to LOCK position. Disconnect scan tool from DLC. Check for poor connections between scan tool and DLC terminals No. 2 (Purple wire) and No. 5 (Black/White wire). See Figure . If no problems are found, go to next step. If problem is found, repair as necessary. After repairs, go to step  27 .
  6. Check for open in ground circuit between DLC terminal No. 5 (Black/White wire) and ground point G102. Ground point G102 is located on steering column support. If ground circuit is okay, go to next step. If ground circuit is open, repair open in Black/White wire. After repairs, go to step  27 .
  7. Disconnect Body Control Module (BCM) 24-pin Light Blue harness connector C2. BCM is located behind left side of instrument panel. See Figure . Check for poor connections at BCM harness connector C2 terminal B7 (Purple wire). See Figure . If no problems are found, go to next step. If problem is found, repair as necessary. After repairs, go to step  27 .
  8. Check for open, short to voltage and short to ground in Purple wire between BCM harness connector C2 terminal B7 and DLC terminal No. 2. See Figure and Figure . If no problems are found, go to next step. If problem is found, repair Purple wire as necessary. After repairs, go to step  27 .
  9. Reconnect BCM harness connector C2. Disconnect Powertrain Control Module (PCM) 80-pin Blue harness connector C1. PCM is located on right front frame rail, in engine compartment. Disconnect radio 24-pin harness connector C1. Disconnect Instrument Panel Cluster (IPC) 12-pin harness connector, located behind center of instrument cluster. Connect scan tool to DLC. Turn ignition switch to RUN position. Using scan tool, attempt to communicate with BCM. If scan tool communicates with BCM, go to next step. If scan tool does not communicate with BCM, go to step  15 .
  10. Turn ignition switch to LOCK position. Reconnect IRC harness connector. Turn ignition switch to RUN position. Using scan tool, attempt to communicate with BCM and IRC. If scan tool communicates with BCM and IRC, go to next step. If scan tool does not communicate with BCM and IRC, go to step  16 .
  11. Turn ignition switch to LOCK position. Disconnect Electronic Brake Control Module (EBCM) 37-pin harness connector. EBCM is located next to brake master cylinder. Reconnect PCM harness connector C1. Turn ignition switch to RUN position. Using scan tool, attempt to communicate with BCM, IRC and PCM. If scan tool communicates with BCM, IRC and PCM, go to next step. If scan tool does not communicate with BCM, IRC and PCM, go to step  17 .
  12. Turn ignition switch to LOCK position. Disconnect Sensing and Diagnostic Module (SDM) 18-pin harness connector. SDM is located under right front seat carpet. Reconnect IPC harness connector. Turn ignition switch to RUN position. Using scan tool, attempt to communicate with BCM, IRC, PCM and IPC on class 2. If scan tool communicates with BCM, IRC, PCM and IPC, go to next step. If scan tool does not communicate with BCM, IRC and PCM, go to step  18 .
  13. Turn ignition switch to LOCK position. Reconnect SDM harness connector. Turn ignition switch to RUN position. Using scan tool, attempt to communicate with BCM, IRC, PCM, IPC and SDM on class 2 serial data circuit. If scan tool communicates 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 switch to LOCK position. Reconnect EBCM harness connector. Turn ignition switch to RUN position. Using scan tool, attempt to communicate with BCM, IRC, PCM, IPC, SDM and EBCM. If scan tool does not communicate with BCM, IRC, PCM, IPC, SDM and EBCM, go to step  20 . If scan tool communicates with BCM, IRC, PCM, IPC, SDM and EBCM, go to step  27 .
  15. Turn ignition switch to LOCK position. Disconnect BCM 16-pin Purple harness connector C1 and BCM 24-pin Light Blue harness connector C2. BCM is located behind left side of instrument panel. See Figure . Check for open, short to ground and short to voltage in Purple wire between BCM harness connector C1 terminal B8 and IRC harness connector C1 terminal A1. See Figure and Figure . Check for open, short to ground and short to voltage in Purple wire between BCM harness connector C2 terminal B8 and PCM harness connector C1 terminal No. 59. See Figure and Figure . Check for open, short to ground and short to voltage in Purple wire between IPC harness connector terminal "L" and BCM harness connector C2 terminal B9. See Figure and Figure . If no problems are found, go to step  21 . If problem is found, repair appropriate Purple wire(s) as necessary. After repairs, go to step  27 .
  16. Turn ignition switch to LOCK position. Disconnect IRC 24-pin harness connector C1, located behind center of instrument panel. Check for open, short to ground and short to voltage in Purple wire between BCM harness connector C1 terminal B8 and radio harness connector C1 terminal A1. See Figure and Figure . Check for poor connections at harness connectors. If no problems are found, go to step  25 . If problem is found, repair Purple wire as necessary. After repairs, go to step  27 .
  17. Turn ignition switch to LOCK position. Disconnect PCM 80-pin Blue harness connector C1. PCM is located on right front frame rail, in engine compartment. Check for open, short to ground and short to voltage in Purple wire between BCM harness connector C2 terminal B8 and PCM harness connector C1 terminal No. 59. See Figure and Figure . Check for open, short to ground and short to voltage in Purple wire between EBCM harness connector C1 terminal C8 and PCM harness connector C1 terminal No. 58. See Figure and Figure . Check for poor connections at harness connectors. If no problems are found, go to step  22 . If problem is found, repair Purple wire as necessary. After repairs, go to step  27 .
  18. Turn ignition switch to LOCK position. Disconnect BCM 24-pin Light Blue harness connector C2. BCM is located behind left side of instrument panel. Disconnect IPC 12-pin harness connector, located behind center of instrument cluster. See Figure . Check for open, short to ground and short to voltage in Purple wire between IPC harness connector terminal "L" and BCM harness connector C2 terminal B9. See Figure and Figure . Check for open, short to ground and short to voltage in Purple wire between IPC harness connector terminal "K" and SDM harness connector terminal A5. See Figure and Figure . Check for poor connections at harness connectors. If no problems are found, go to step  23 . If problem is found, repair Purple wire as necessary. After repairs, go to step  27 .
  19. Turn ignition switch to LOCK position. Disconnect IPC 12-pin harness connector, located behind center of instrument cluster. Disconnect SDM 18-pin harness connector, located under right front seat carpet. Check for open, short to ground and short to voltage in Purple wire between IPC harness connector terminal "K" and SDM harness connector terminal A5. See Figure and Figure . Check for poor connections at IPC and SDM harness connectors. Check for open, short to ground and short to voltage in Purple wire between SDM harness connector terminal A4 and EBCM harness connector C1 terminal B7. See Figure and Figure . If no problems are found, go to step  24 . If problem is found, repair Purple wire as necessary. After repairs, go to step  27 .
  20. Turn ignition switch to LOCK position. Disconnect SDM 18-pin harness connector, located under right front seat carpet. Disconnect BCM 24-pin Light Blue harness connector C2. BCM is located behind left side of instrument panel. Disconnect PCM 80-pin Blue harness connector C1. PCM is located on right front frame rail, in engine compartment. Check for poor connections at harness connectors. If no problems are found, go to step  26 . If problem is found, repair Purple wire as necessary. After repairs, go to step  27 .
  21. Replace BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. After repairs, go to step  27 .
  22. Replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. After repairs, go to step  27 .
  23. Replace instrument panel cluster. See INSTRUMENT PANEL CLUSTER  under REMOVAL & INSTALLATION. After repairs, go to step  27 .
  24. Replace SDM. See SENSING & DIAGNOSTIC MODULE  under REMOVAL & INSTALLATION. After repairs, go to step  27 .
  25. Replace IRC. After repairs, go to step  27 .
  26. Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE  under REMOVAL & INSTALLATION. After repairs, go to next step.
  27. Reconnect all module harness connectors. Connect scan tool to DLC located at lower left side of instrument panel, near steering column. Turn ignition switch to RUN position. Wait 10 seconds. Scan tool may require a power up reset before communication will occur if class 2 serial data circuit was shorted. Attempt to communicate with each module on class 2 serial data circuit. If scan tool communicates with each module, go to next step. If scan tool does not communicate with each module, go to step  2 .
    28. NOTE: If using Tech 2 scan tool, use CLASS 2 DTC check feature in order to determine which modules have DTCs set.
  28. Using scan tool, select DISPLAY DTCs function. Record all retrieved DTCs and DTC status. If no DTCs beginning with "U" are retrieved, go to next step. If DTCs are retrieved that begin with "U" and are current DTCs, go to step  30 .
  29. If DTCs were retrieved that do not begin with "U", go to next step. If no DTCs were retrieved that do not begin with "U", go to step  32 .
  30. Perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . For DTCs not listed, attempt to diagnose malfunctioning system or device by symptom. Go to appropriate article for malfunctioning system or device. After repair, go to next step.
  31. If all DTCs have been diagnosed, go to next step. If any DTCs have not been diagnosed, go to step  30 .
  32. Using scan tool, clear DTCs. System is okay at this time.
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