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Test F: No Module/Network Communication - ISO 9141 Link

NOTE: Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.
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). See Figure. This is the International Standards Organization (ISO) 9141 diagnostic communications network circuit.
  1. Turn ignition switch to LOCK position. Inspect Data Link Connector (DLC) terminal No. 7 (Light Blue/White wire) for looseness, damage or corrosion. See Figure. DLC is located under instrument panel between steering column and the radio. See Figure. If DLC terminal is faulty, repair or replace as necessary. If terminal is okay, disconnect Generic Electronic Module (GEM) 26-pin harness connector C201e. See Figure. GEM is located behind left side of instrument panel, next to central junction box. See Figure. Measure resistance between GEM harness connector C201e terminal No. 6 and DLC terminal No. 7 (Light Blue/White wire). If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open circuit in Light Blue/White wire between GEM and DLC. For DATA LINK CONNECTOR circuit identification. See WIRING DIAGRAMS .
  2. Turn ignition switch to RUN position. Connect positive lead of a DVOM to DLC terminal No. 7 (Light Blue/White wire). See Figure. While observing voltage reading, connect negative lead of DVOM to DLC terminals No. 4 (Black wire), then No. 16 (Light Green/Red wire). If either measurement indicates zero volts, go to next step. If both measurements indicate voltage, replace GEM. See GENERIC ELECTRONIC MODULE  under REMOVAL & INSTALLATION.
  3. Turn ignition switch to LOCK position. Reconnect GEM harness connector C201e and disconnect 16-pin in-line harness connector C314. See Figure. In-line 16-pin harness connector C314 is located behind left side of instrument panel, next to central junction box. See Figure. Turn ignition switch to RUN position. Connect positive lead of a DVOM to DLC terminal No. 7 (Light Blue/White wire). See Figure. While observing voltage reading, connect negative lead of DVOM to DLC terminals No. 4 (Black wire), then No. 16 (Light Green/Red wire). See Figure. If either measurement indicates zero volts, go to next step. If both measurements indicate voltage, go to step  5.
  4. Turn ignition switch to LOCK position. Disable air bag system. See appropriate AIR BAG RESTRAINT SYSTEMS article in RESTRAINT. Disconnect Restraint Control Module (RCM) 26-pin harness connector C2041. See Figure. RCM is located behind left side of instrument panel, next to central junction box. See Figure. Turn ignition switch to RUN position. Connect positive lead of a DVOM to DLC terminal No. 7 (Light Blue/White wire). While observing voltage reading, connect negative lead of DVOM to DLC terminals No. 4 (Black wire), then No. 16 (Light Green/Red wire). See Figure. If either measurement indicates zero volts, repair short circuit in Light Blue/White wire between DLC, GEM, RCM and in-line harness connector C331. For DATA LINK CONNECTOR identification. See WIRING DIAGRAMS . If both measurements indicate voltage, replace RCM. See appropriate AIR BAG RESTRAINT SYSTEMS article in RESTRAINT.
  5. Turn ignition switch to LOCK position. Reconnect in-line harness connector C314. See Figure. If vehicle is equipped with ABS (with or without traction control), go to next step. If vehicle is not equipped with ABS, go to step  7.
  6. Disconnect ABS 30-pin module harness connector C135. See Figure. ABS control module is located in right front of engine compartment, behind radiator. See Figure. Turn ignition switch to RUN position. Connect positive lead of a DVOM to DLC terminal No. 7 (Light Blue/White wire). While observing voltage reading, connect negative lead of DVOM to DLC terminals No. 4 (Black wire), then No. 16 (Light Green/Red wire). See Figure. If either measurement indicates zero volts, go to next step. If both measurements indicate voltage, replace ABS control module. See ANTI-LOCK BRAKE CONTROL MODULE  under REMOVAL & INSTALLATION.
  7. Turn ignition switch to LOCK position. Disconnect 16-pin in-line harness connector C140. See Figure. 16-pin in-line harness connector C107 is located in left rear corner of engine compartment. See Figure. Turn ignition switch to RUN position. Connect positive lead of a DVOM to DLC terminal No. 7 (Light Blue/White wire). While observing voltage reading, connect negative lead of DVOM to DLC terminals No. 4 (Black wire), then No. 16 (Light Green/Red wire). See Figure. If either measurement indicates zero volts, repair short circuit in Light Blue/White wire between in-line harness connectors C140 and C314. If both measurements indicate voltage, repair short circuit in Light Blue/White wire between in-line harness connector C140 and ABS control module.
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