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Test N: No Module/Network Communication - SCP Bus Link

NOTE: Depending on module configuration, with all modules connected and with ignition switch in RUN position or with engine running, 2-3 volts may be present at Data Link Connector (DLC) terminals No. 2 (Gray/Red wire) and No. 10 (Blue/Red wire). These are the Standard Corporate Protocol (SCP) diagnostic communications network circuits.
NOTE: Anti-Lock Brake System (ABS) control module is referred to as a Stability Assist Module (SAM) if vehicle is equipped with traction control and stability assist. Audio Control Module (ACM) may also be referred to as audio unit. Next Generation Speed Control (NGSC) servo is an integral part of the Powertrain Control Module (PCM). Message center module is an integral part of the instrument cluster. Steering Column Lock Module (SCLM) may also be referred to as a Steering Column Lock Unit (SCLU) or steering column lock.
NOTE: Remote Emergency Satellite Cellular Unit (RESCU) module, Driver's Seat Module (DSM) and Steering Column Lock Module (SCLM) will fail data link diagnostic test if vehicle is not equipped with that module(s). Vehicles with voice activated cellular phone are equipped with a RESCU module. Vehicles with memory seats are equipped with a DSM. Vehicles with a manual transmission are equipped with a SCLM.
  1. Inspect NGS tester connector for loose, damaged or corroded terminals. If problem exists, repair connector as necessary and retest system for normal operation. If problem does not exist, go to next step.
  2. Turn ignition switch to LOCK position. Inspect Data Link Connector (DLC) for physical damage, bent terminals or corrosion. If problem exists, repair connector as necessary and retest system for normal operation. If problem does not exist, go to next step.
  3. Turn ignition switch to LOCK position. Disconnect joint connector No. 4 harness connector C223, located behind left side of instrument panel. Measure resistance in Gray/Red wire between terminal No. 14 at joint connector No. 4 harness connector C223 and terminal No. 2 at DLC. See Figure and Figure . Measure resistance in Blue/Red wire between terminal No. 9 at joint connector No. 4 harness connector C223 and terminal No. 10 at DLC. If both resistances are 5 ohms or less, go to next step. If either resistance is greater than 5 ohms, repair open in appropriate wire between joint connector No. 4 and DLC. Retest system for normal operation.
  4. Turn ignition switch to RUN position. Measure voltage between terminals No. 4 (Black wire) and No. 2 (Gray/Red wire) at DLC. See Figure . Measure voltage between terminal No. 16 (Orange/Yellow wire) and No. 2 (Gray/Red wire) at DLC. Measure voltage between terminals No. 4 (Black wire) and No. 10 (Blue/Red wire) at DLC. See Figure . Measure voltage between terminal No. 16 (Orange/Yellow wire) and No. 10 (Blue/Red wire) at DLC. If voltage is indicated in any measurement, repair short to ground or voltage in wiring between DLC and joint connector No. 4. If voltage is not indicated in any measurement, go to next step.
  5. Measure resistance between terminals No. 9 and 11 at joint connector No. 4 (component side). See Figure . Measure resistance between terminals No. 12 and 14 at joint connector No. 4 (component side). If both resistances are 5 ohms or less, go to next step. If either resistance is greater than 5 ohms, replace joint connector No. 4 and retest system for normal operation.
  6. Connect joint connector No. 4 harness connector C223. Disconnect Auxiliary Junction Box (AJB) harness connector C283d, located behind left side of instrument panel. See Figure . Connect NGS tester. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If ACM, ICM, DATC module and/or SCLM (if equipped) did not pass, go to next step. If ACM, ICM, DATC module and SCLM (if equipped) all passed, go to step  13 .
  7. Turn ignition switch to LOCK position. Disconnect ACM harness connector C240a. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If ACM, ICM, DATC module and SCLM did not pass, go to next step if equipped with SCLM or go to step  11 if not equipped with SCLM. If ICM, DATC module and SCLM all passed, replace ACM.
  8. Turn ignition switch to LOCK position. Disconnect SCLM harness connector C267. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If ACM, ICM, DATC module and SCLM did not pass, go to next step. If ICM and DATC module both passed, replace SCLM.
  9. Turn ignition switch to LOCK position. Disconnect in-line harness connector C248, located above steering column "U" joint. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If ACM, ICM, DATC and SCLM did not pass, go to next step. If ICM and DATC module both passed, repair short to ground or voltage in Gray/Orange wire between in-line harness connector C248 and SCLM.
  10. Turn ignition switch to LOCK position. Disconnect DATC module harness connector C228a. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If ACM, ICM, DATC module and SCLM did not pass, go to next step. If ICM passed, replace DATC module.
  11. Turn ignition switch to LOCK position. Disconnect instrument cluster harness connector C220b. Turn ignition switch to RUN position. Measure voltage between terminals No. 4 (Black wire) and No. 2 (Gray/Red wire) at DLC. Measure voltage between terminals No. 2 (Gray/Red wire) and No. 16 (Orange/Yellow wire) at DLC. Measure voltage between terminals No. 4 (Black wire) and No. 10 (Blue/Red wire) at DLC. Measure voltage between terminals No. 10 (Blue/Red wire) and No. 16 (Orange/Yellow wire) at DLC. If voltage is not indicated in all measurements, go to next step. If voltage is indicated in all measurements, replace instrument cluster.
  12. Turn ignition switch to LOCK position. Disconnect joint connector No. 4 harness connector C223. Turn ignition switch to RUN position. Measure voltage between terminal No. 4 (Black wire) at DLC and appropriate terminals at joint connector No. 4 harness connector C223. Measure voltage between terminal No. 16 (Orange/Yellow wire) at DLC and appropriate terminals at joint connector No. 4 harness connector C223. See BUS CIRCUIT IDENTIFICATION  table. See Figure and Figure . If voltage is indicated in any measurement, repair short to ground or voltage in appropriate circuit. If voltage is not indicated in any measurement, replace joint connector No. 4.
    BUS CIRCUIT IDENTIFICATION

    Terminal No. Wire Color
    6 (1) Blue/Black
    7 Blue/Yellow
    8 Blue/Yellow
    10 Blue/White
    11 Blue
    12 Gray
    13 Gray/Violet wire
    15 Gray/Black
    16 Gray/Black
    17 (1) Gray/Orange
    (1) This circuit only exists if vehicle is equipped with SCLM.
  13. Turn ignition switch to LOCK position. Connect AJB harness connector C283d. Disconnect AJB harness connector C283a. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If only DDM and DSM did not pass, go to next step. If more than DDM and DSM did not pass, go to step  17 .
  14. Turn ignition switch to LOCK position. Connect AJB harness connector C283a. Disconnect DDM harness connector C501a, located behind driver's door panel. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If only DDM did not pass, replace DDM. If more than DDM did not pass, go to next step.
  15. If vehicle is equipped with DSM, go to next step. If vehicle is not equipped with DSM, repair short to ground or voltage in wiring between AJB and DDM.
  16. Turn ignition switch to LOCK position. Disconnect DSM harness connector C341c, located under driver's seat. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If only DDM and DSM did not pass, replace DSM. If more than DDM and DSM did not pass, repair short to ground or voltage in wiring between AJB and DSM, or between AJB and DDM.
  17. Turn ignition switch to LOCK position. Disconnect AJB harness connector C283b. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If only DDM, REM, DSM and RESCU module (if equipped) did not pass, go to next step. If more than DDM, REM, DSM and RESCU module (if equipped) did not pass, go to step  22 .
  18. If vehicle is equipped with RESCU module, go to next step. If vehicle is not equipped with RESCU module, go to step  21 .
  19. Turn ignition switch to LOCK position. Connect AJB harness connector C283b. Disconnect RESCU module harness connector. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If only DDM, DSM and RESCU module did not pass, replace RESCU module. If more than DDM, DSM and RESCU module did not pass, go to next step.
  20. Turn ignition switch to LOCK position. Disconnect REM 22-pin harness connector C420b. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If only DDM, REM, DSM and RESCU module did not pass, replace REM. If more than DDM, REM, DSM and RESCU module did not pass, repair short to ground or voltage in wiring between AJB and REM, or between AJB and RESCU module.
  21. Turn ignition switch to LOCK position. Connect AJB harness connector C283b. Disconnect REM 22-pin harness connector C420b. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If only DDM, REM and DSM did not pass, replace REM. If more than DDM, REM and DSM did not pass, repair short to ground or voltage in wiring between AJB and REM.
  22. Turn ignition switch to LOCK position. Disconnect AJB harness connector C283c. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If only DDM, REM, FEM, ABS control module, PCM, DSM and RESCU module (if equipped) did not pass, go to next step. If more than DDM, REM, FEM, ABS control module, PCM, DSM and RESCU module (if equipped) did not pass, repair short to ground or voltage in AJB.
  23. Turn ignition switch to LOCK position. Connect AJB harness connector C283c. Disconnect FEM harness connector C201c. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If more than DDM, REM, FEM, DSM and RESCU module (if equipped) did not pass, go to next step. If only DDM, REM, FEM, DSM and RESCU module (if equipped) did not pass, replace FEM.
  24. Turn ignition switch to LOCK position. Disconnect ABS control module harness connector. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If more than DDM, REM, FEM, ABS control module, DSM and RESCU module (if equipped) did not pass, go to next step. If only DDM, REM, FEM, ABS control module, DSM and RESCU module (if equipped) did not pass, replace ABS control module.
  25. Turn ignition switch to LOCK position. Disconnect PCM harness connector C175a. Turn ignition switch to RUN position. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If only DDM, REM, FEM, ABS control module, PCM, DSM and RESCU module (if equipped) did not pass, replace PCM. If more than DDM, REM, FEM, ABS control module, PCM, DSM and RESCU module (if equipped) did not pass, repair short to ground or voltage in wiring between AJB and FEM, ABS control module, PCM and/or ABS test connector.
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