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Test C: Scan Tool Does Not Communicate With Electronic Brake Control Module

  1. If data link communications system check has been performed, go to next step. If data link communications system check has not been performed, perform data link communications system check. Perform DATA LINK DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel, right of steering column. Attempt to communicate with same system on a different vehicle. If communication is established, go to next step. If communication is not established, go to step  4 .
  3. Turn ignition switch to LOCK position. Inspect scan tool cable connector and DLC for proper connection. If scan tool cable connector and DLC are okay, go to step  5 . If scan tool cable connector and DLC are not okay, go to step  6 .
  4. Scan tool may be defective. Use scan tool manufacturer's manual to diagnose scan tool. After repair, perform DATA LINK DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  5. Disconnect Electronic Brake Control Module (EBCM) and Sensing and Diagnostic Module (SDM). EBCM is located under left side of instrument panel, above junction block. SDM is located under center console. Measure resistance between terminals No. 9 (Purple wire) and No. 5 (Black wire). See Figure . If resistance is 2 ohms or more, go to step  7 . If resistance is less than 2 ohms, go to step  8 .
  6. Repair DLC or scan tool as necessary. After repairs, perform DATA LINK DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  7. Measure voltage between terminals No. 5 (Black wire) and No. 9 (Purple wire). See Figure . If voltage does not exist, go to step  9 . If any voltage exists, go to step  10 .
  8. Repair short to ground in circuit between DLC and Electronic Brake Control Module (EBCM) or between Sensing and Diagnostic Module (SDM) and DLC. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, perform DATA LINK DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  9. Measure voltage between ground and DLC terminal No. 16 (White wire). See Figure . If battery voltage exists, go to step  11 . If battery voltage does not exist, go to step  12 .
  10. Repair short to voltage in circuit between DLC and Electronic Brake Control Module (EBCM) or between Sensing and Diagnostic Module (SDM) and DLC. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, perform DATA LINK DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  11. Check for an open in circuit between DLC and Electronic Brake Control Module (EBCM) or between Sensing and Diagnostic Module (SDM) and DLC. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. If Purple wire is okay and concern is related to Anti-Lock Brake System (ABS), diagnose ABS. See appropriate ANTI-LOCK article in BRAKES. If Purple/Red wire is okay and concern is related to air bag system, diagnose air bag system. For information on air bag DIAGNOSIS & TESTING or DISPOSAL PROCEDURES, see lemon-25(R) AIR BAG SERVICE & REPAIR MANUAL, DOMESTIC & IMPORTED MODELS. After repairs, perform DATA LINK DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  12. Repair open in White wire between junction block and DLC. After repair, perform DATA LINK DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
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