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Test B: No Module/Network Communication - ISO 9141 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) terminal No. 7 (Light Blue/White wire). This is the International Standards Organization (ISO) 9141 diagnostic communications network circuit.
NOTE: After making any repair, perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM.
  1. Turn ignition switch to LOCK position. Inspect NGS tester connector for loose, damaged or corroded terminals. If connector is okay, go to next step. If problem exists, repair connector as necessary.
  2. Inspect Data Link Connector (DLC) for physical damage, bent terminals or corrosion. If connector is okay, go to next step. If problem exists, repair as necessary.
  3. Disconnect Generic Electronic Module (GEM) harness connector C236. See Fig 1 . Measure resistance in Light Blue/White wire between terminal No. 10 at GEM harness connector C236 and terminal No. 7 at DLC. See Figure and Fig 2 . If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Light Blue/White wire between GEM and DLC.
  4. If vehicle is equipped with Anti-Lock Brake System (ABS), go to next step. If vehicle is not equipped with ABS, go to step  7 .
  5. Disconnect Anti-Lock Brake System (ABS) module harness connector C1057. Turn ignition switch to RUN position. Perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 70 = ALL ECUS NO RESP/NOT EQUIP, go to next step. If NGS tester does not display CKT 70 = ALL ECUS NO RESP/NOT EQUIP, replace ABS module.
  6. Turn ignition switch to LOCK position. Disconnect in-line harness connector C221. See Fig 1 . Turn ignition switch to RUN position. Perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 70 = ALL ECUS NO RESP/NOT EQUIP, go to next step. If NGS tester does not display CKT 70 = ALL ECUS NO RESP/NOT EQUIP, repair Light Blue/White wire between in-line harness connector C221 and ABS module.
  7. Turn ignition switch to LOCK position. Connect ABS module connector C1057 (if disconnected). Disconnect GEM harness connector C236. See Fig 1 . Turn ignition switch to RUN position. Perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 70 = ALL ECUS NO RESP/NOT EQUIP, go to next step. If NGS tester does not display CKT 70 = ALL ECUS NO RESP/NOT EQUIP, replace GEM module.
  8. Turn ignition switch to LOCK position. Disconnect in-line harness connector C214. See Fig 1 . Turn ignition switch to RUN position. Perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester does not display CKT 70 = ALL ECUS NO RESP/NOT EQUIP, go to next step. If NGS tester displays CKT 70 = ALL ECUS NO RESP/NOT EQUIP, repair Light Blue/White wire between GEM, in-line harness connector C214, in-line harness connector C221 and DLC.
  9. Turn ignition switch to LOCK position. Connect GEM harness connector and in-line harness connector C214. Deactivate air bag system. See appropriate AIR BAG RESTRAINT SYSTEMS article. Disconnect electronic crash sensor module harness connector C277. See Fig 1 . Turn ignition switch to RUN position. Perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 70 = ALL ECUS NO RESP/NOT EQUIP, go to next step. If NGS tester does not display CKT 70 = ALL ECUS NO RESP/NOT EQUIP, replace electronic crash sensor module.
  10. Turn ignition switch to LOCK position. If vehicle is equipped with Remote Anti-Theft Personality (RAP) module, go to next step. If vehicle is not equipped with RAP module, go to step  12 .
  11. Turn ignition switch to LOCK position. Disconnect Remote Anti-Theft Personality (RAP) module harness connector C253. See Fig 1 . Turn ignition switch to RUN position. Perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 70 = ALL ECUS NO RESP/NOT EQUIP, go to next step. If NGS tester does not display CKT 70 = ALL ECUS NO RESP/NOT EQUIP, replace RAP module.
  12. Turn ignition switch to LOCK position. If vehicle is equipped with Semi-Active Ride Control (SARC) module, go to next step. If vehicle is not equipped with SARC module, repair Light Blue/White wire between in-line harness connector C214, RAP module and electronic crash sensor module.
  13. Turn ignition switch to LOCK position. Disconnect Semi-Active Ride Control (SARC) module harness connector C451. Turn ignition switch to RUN position. Perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 70 = ALL ECUS NO RESP/NOT EQUIP, repair Light Blue/White wire between in-line harness connector C214, RAP module, electronic crash sensor module and SARC module. If NGS tester does not display CKT 70 = ALL ECUS NO RESP/NOT EQUIP, replace SARC module.
Fig 1: Locating Harness Connectors Behind Instrument Panel
G99I08222Courtesy of FORD MOTOR CO.
Fig 2: Identifying GEM Harness Connector C236 Terminals
G98G08141Courtesy of FORD MOTOR CO.
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