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Test E: No Module/Network Communications - 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 (Orange/Blue wire). This is the International Standards Organization (ISO) 9141 diagnostic communications network circuit.
NOTE: When performing the following test, the NGS tester may display ISO circuit No. 170 as circuit No. 70.
  1. Inspect NGS tester connector for loose, damaged or corroded terminals. Pay particular attention to terminals No. 4 and 7. Repair as necessary and retest system for normal operation. If connector is okay, inspect Data Link Connector (DLC) for loose, damaged or corroded terminals. Pay particular attention to terminals No. 4 (Black wire) and No. 7 (Orange/Blue wire). Repair as necessary and retest system for normal operation. If connector is okay, go to next step.
  2. Turn ignition on. Measure voltage between terminals No. 7 (Orange/Blue wire) and No. 5 (Blue/Orange wire) at DLC. See Figure . If any voltage is indicated, go to step  5 . If no voltage is indicated, go to next step.
  3. Turn ignition off. Measure voltage between terminals No. 7 (Orange/Blue wire) and No. 16 (Green wire) at DLC. If voltage is indicated, go to step  5 . If no voltage is indicated, go to next step.
  4. Turn ignition off. Disconnect Blue 14-pin in-line connector located near clutch pedal position switch. See Figure . Measure resistance of Orange/Blue wire between terminal No. 7 at DLC and terminal No. 5 at in-line connector C229. See Figure and Fig 1 . If resistance is less than 5 ohms, repair Orange/Blue wire between connectors C229, C222 and C262. Retest system for normal operation. If resistance is 5 ohms or more, repair open Orange/Blue wire between in-line connector C229 and DLC. Retest system for normal operation.
  5. Turn ignition off. Disconnect Blue 14-pin in-line connector located near clutch pedal position switch. See Figure . Turn ignition on. Measure voltage between terminals No. 7 (Orange/Blue wire) and No. 16 (Green wire) at DLC. Also, measure voltage between terminals No. 7 (Orange/Blue wire) and No. 4 (Black wire) at DLC. See Figure . If voltage is indicated at any terminal, repair Orange/Blue wire between DLC and in-line connector C229. Retest system for normal operation. If no voltage is indicated at any terminal, reconnect in-line connector C229 and go to next step.
  6. If vehicle is equipped with Anti-Lock Brake System (ABS) module and/or Remote Anti-Theft Personality (RAP) module, go to next step. If vehicle is only equipped with a air bag diagnostic monitor, go to step  8 .
  7. Turn ignition off. Deactivate air bag system. See AIR BAG RESTRAINT SYSTEMS - ESCORT & TRACER article. Disconnect air bag diagnostic monitor connector under front of center console. Reconnect positive battery cable and then negative battery cable. Turn ignition on. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 170 = ALL ECUS NO RESP/NOT EQUIP, go to step  10 . If NGS tester does not display CKT 170 = ALL ECUS NO RESP/NOT EQUIP, replace air bag diagnostic monitor and retest system for normal operation.
  8. Turn ignition off. Disconnect NGS tester. Deactivate air bag system. See AIR BAG RESTRAINT SYSTEMS - ESCORT & TRACER article. Disconnect air bag diagnostic monitor connector under front of center console. Reconnect positive battery cable and then negative battery cable. Turn ignition on. Measure voltage between terminals No. 7 (Orange/Blue wire) and No. 16 (Green wire) at DLC. Also, measure voltage between terminals No. 7 (Orange/Blue wire) and No. 4 (Black wire) at DLC. See Figure . If voltage is indicated at any terminals, go to next step. If no voltage is indicated, replace air bag diagnostic monitor and retest system for normal operation.
  9. Turn ignition off. Disconnect White 6-pin in-line connector C233 located behind left side of instrument panel. See Figure . Turn ignition on. Measure voltage between terminals No. 7 (Orange/Blue wire) and No. 16 (Green wire) at DLC. Also, measure voltage between terminals No. 7 (Orange/Blue wire) and No. 4 (Black wire) at DLC. See Figure . If voltage is indicated at any terminals, repair Orange/Blue wire between in-line connectors C229 and C233. Retest system for normal operation. If no voltage is indicated, repair Orange/Blue wire between in-line connector C233 and air bag diagnostic monitor connector. Retest system for normal operation.
  10. Turn ignition off. Disconnect White 6-pin in-line connector C233 located behind left side of instrument panel. See Figure . Turn ignition on. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 170 = ALL ECUS NO RESP/NOT EQUIP, go to next step. If NGS tester does not display CKT 170 = ALL ECUS NO RESP/NOT EQUIP, repair Orange/Blue wire between in-line connector C233 and air bag diagnostic monitor connector. Retest system for normal operation.
  11. If vehicle is equipped with an ABS module and a RAP module, go to next step. If vehicle is only equipped with a RAP module, go to step  13 .
  12. Disconnect RAP module 26-pin connector C405. On coupe and sedans, RAP module is behind right rear quarter panel. On station wagons, RAP module is behind left rear quarter panel. On all models, turn ignition on. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 170 = ALL ECUS NO RESP/NOT EQUIP, go to step  15 . If NGS tester does not display CKT 170 = ALL ECUS NO RESP/NOT EQUIP, replace RAP module and retest system for normal operation.
  13. Turn ignition off. Disconnect NGS tester and RAP module 26-pin connector C405. On coupe and sedans, RAP module is behind right rear quarter panel. On wagons, RAP module is behind left rear quarter panel. On all models, turn ignition on. Measure voltage between terminals No. 7 (Orange/Blue wire) and No. 16 (Green wire) at DLC. Also, measure voltage between terminals No. 7 (Orange/Blue wire) and No. 4 (Black wire) at DLC. See Figure . If voltage is indicated at any terminal, go to next step. If no voltage is indicated at any terminal, replace RAP module and retest system for normal operation.
  14. Turn ignition off. Disconnect Black 17-pin in-line connector C222 located behind left side of instrument panel, near fuse block. See Figure . Turn ignition on. Measure voltage between terminals No. 7 (Orange/Blue wire) and No. 16 (Green wire) at DLC. Also, measure voltage between terminals No. 7 (Orange/Blue wire) and No. 4 (Black wire) at DLC. See Figure . If voltage is indicated at any terminal, repair Orange/Blue wire between connectors C229, C233 and C222. Retest system for normal operation. If no voltage is indicated at any terminal, repair Orange/Blue wire between RAP module connectors C405 and C222. Retest system for normal operation.
  15. Turn ignition off. Disconnect Black 17-pin in-line connector C222 located behind left side of instrument panel, near fuse block. See Figure . Disconnect NGS tester. Turn ignition on. Perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST  under SELF-DIAGNOSTIC SYSTEM. If NGS tester displays CKT 170 = ALL ECUS NO RESP/NOT EQUIP (Escort ZX2 may display CKT131=00000003), go to next step. If NGS tester does not display CKT 170 = ALL ECUS NO RESP/NOT EQUIP, repair Orange/Blue wire between in-line connector C222 and RAP module connector C405. Retest system for normal operation.
  16. If vehicle is equipped with an ABS module, go to next step. If vehicle is not equipped with an ABS module, system is functioning properly at this time. Testing is complete.
  17. Turn ignition off. Disconnect ABS control module 40-pin connector located under front passenger's seat. Disconnect NGS tester. Turn ignition on. Measure voltage between terminals No. 7 (Orange/Blue wire) and No. 16 (Green wire) at DLC. Also, measure voltage between terminals No. 7 (Orange/Blue wire) and No. 4 (Black wire) at DLC. See Figure . If voltage is indicated at any terminal, go to next step. If no voltage is indicated at any terminal, replace ABS module and retest system for normal operation.
  18. Turn ignition off. Disconnect Black 18-pin in-line connector C262. See Figure . Turn ignition on. Measure voltage between terminals No. 7 (Orange/Blue wire) and No. 16 (Green wire) at DLC. Also, measure voltage between terminals No. 7 (Orange/Blue wire) and No. 4 (Black wire) at DLC. See Figure . If voltage is indicated at any terminal, repair Orange/Blue wire between in-line connectors C262, C229, C222 (if equipped) and C233. Retest system for normal operation. If no voltage is indicated at any terminal, replace ABS module and retest system for normal operation.
Fig 1: Identifying Connector C229 Terminals (Male Half Of Connector Shown)
G98H01710Courtesy of FORD MOTOR CO.
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