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Test I: 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 (Light Blue/White wire). This is the International Standards Organization (ISO) 9141 diagnostic communications network circuit.
  1. Turn ignition switch to LOCK position. Turn ignition switch to LOCK position. Inspect Data Link Connector (DLC) for physical damage, bent terminals or corrosion. If problem does not exist, go to next step. If problem exists, repair as necessary and retest system.
  2. Disconnect Lighting Control Module (LCM) harness connector C2027. See Figure . Measure resistance in Light Blue/White wire between terminal No. 8 at LCM harness connector C2027 and terminal No. 7 at DLC. See Figure and Figure . 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 LCM harness connector C2027 and DLC.
  3. Turn ignition switch to RUN position. Measure voltage between terminals No. 7 (Light Blue/White wire) and No. 16 (Yellow/Black wire) at DLC. See Figure . Also, measure voltage between terminals No. 7 (Light Blue/White wire) and No. 4 (Black wire) at DLC. If any reading indicates voltage, go to next step (vehicle with driver's door module) or go to step  7 (vehicle without driver's door module). If both readings indicate zero volts, replace LCM.
  4. Turn ignition switch to LOCK position. Disconnect Driver's Door Module (DDM) harness connector C518. Inspect harness connector for loose, damaged or corroded terminals. See Figure . If problem does not exist, go to next step. If problem exists, repair as necessary and retest system.
  5. Turn ignition switch to RUN position. Measure voltage between terminals No. 7 (Light Blue/White wire) and No. 16 (Yellow/Black wire) at DLC. See Figure . Also, measure voltage between terminals No. 7 (Light Blue/White wire) and No. 4 (Black wire) at DLC. If any reading indicates voltage, go to next step. If both readings indicate zero volts, replace DDM.
  6. Turn ignition switch to LOCK position. Disconnect in-line harness connector C211. See Figure . Turn ignition switch to RUN position. Measure voltage between terminals No. 7 (Light Blue/White wire) and No. 16 (Yellow/Black wire) at DLC. See Figure . Also, measure voltage between terminals No. 7 (Light Blue/White wire) and No. 4 (Black wire) at DLC. If any reading indicates voltage, go to next step. If both readings indicate zero volts, repair short to voltage or ground in Light Blue/White wire between harness connector C211 and DDM.
  7. Turn ignition switch to LOCK position. Deactivate air bag system. See appropriate AIR BAG RESTRAINT SYSTEMS article. Connect LCM harness connector C2027. Disconnect Electronic Crash Sensor (ECS) module harness connector C277. Inspect ECS module harness connector for loose, damaged or corroded terminals. If problem does not exist, go to next step. If problem exists, repair as necessary and retest system.
  8. Turn ignition switch to LOCK position. Disconnect in-line harness connector C211. See Figure . Turn ignition switch to RUN position. Measure voltage between terminals No. 7 (Light Blue/White wire) and No. 16 (Yellow/Black wire) at DLC. See Figure . Also, measure voltage between terminals No. 7 (Light Blue/White wire) and No. 4 (Black wire) at DLC. If any reading indicates voltage, repair short to voltage or ground in Light Blue/White wire between DLC, harness connector C211, ECS module and DDM. If both readings indicate zero volts, replace ECS module.
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