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Possible Causes

WARNING: This page is about a different car, the 2002 Lincoln Blackwood. However, it is still accessible from the selected car via links, so may be relevant.

A left side crash sensor communication fault could be caused by damaged White/Light Green wire (circuit No. 1261), damaged Brown/Light Green wire (circuit No. 1262) or damaged left side crash sensor.

  1. Check for hard or intermittent DTCs

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). See USING SCAN TOOL  under DIAGNOSTICS. Turn ignition switch to RUN position. Retrieve and record any continuous DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES (DTCS)  under DIAGNOSTICS. Clear continuous DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC U2017 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC U2017 was not retrieved, fault is intermittent. Go to step  9 .

  2. Check harness connector

    Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Access left side crash sensor. See SIDE CRASH SENSOR  under REMOVAL & INSTALLATION. Visually check left side crash sensor harness connection. If left side crash sensor harness connector is properly connected to sensor, go to next step. If left side crash sensor harness connector is not properly connected to sensor, reconnect connector. Go to step  10 .

  3. Check for open circuit

    Access RCM and disconnect harness connector C2041B. See RESTRAINTS CONTROL MODULE (RCM)  under REMOVAL & INSTALLATION. Disconnect left side crash sensor harness connector. Measure resistance of White/Light Green wire between harness side of RCM connector C2041B, terminal No. 8 and harness side of left side crash sensor connector. If resistance is more than one ohm, repair open in White/Light Green wire. See WIRING DIAGRAMS  . Go to step  10 . If resistance is less than one ohm, go to next step.

  4. Check for open circuit

    Measure resistance of Brown/Light Green wire between harness side of RCM connector C2041B, terminal No. 9 and harness side of left side crash sensor harness connector. If resistance is more than one ohm, repair open in Brown/Light Green wire. Go to step  10 . If resistance is less than one ohm, go to next step.

  5. Check for short to ground

    Disconnect RCM connector C2041A. Measure resistance between harness side of RCM connector C2041B, terminal No. 8 (White/Light Green wire) and harness side of RCM connector C2041A, terminal No. 21 (Black/Orange wire, circuit No. 649). If resistance is less than 10 k/ohms, repair short to ground in White/Light Green wire. Go to step  10 . If resistance is more than 10 k/ohms, go to next step.

  6. Check for short to ground

    Measure resistance between harness side of RCM connector C2041B, terminal No. 9 (Brown/Light Green wire) and harness side of RCM connector C2041A, terminal No. 21 (Black/Orange wire). If resistance is less than 10 k/ohms, repair short to ground in Brown/Light Green wire. Go to step  10 . If resistance is more than 10 k/ohms, go to next step.

  7. Check for short to voltage

    Turn ignition switch to RUN position. Measure voltage between ground and harness side of RCM connector C2041B, terminal No. 8 (White/Light Green wire). If voltage is less than 0.2 volt, go to next step. If voltage is more than 0.2 volt, repair short to voltage in White/Light Green wire. Go to step  10 .

  8. Check for short to voltage

    Measure voltage between ground and harness side of RCM connector C2041B, terminal No. 9 (Brown/Light Green wire). If voltage is less than 0.2 volt, go to next step. If voltage is more than 0.2 volt, repair short to voltage in Brown/Light Green wire. Go to step  10 .

  9. Check for intermittent fault

    Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. If DTC retrieved in step  1 was an intermittent fault, check for cause of intermittent left side crash sensor communication fault. Attempt to recreate fault by flexing wire harness and cycling ignition switch frequently. Repair any intermittent problems found. Go to next step. If DTC retrieved in step  1 was not an intermittent fault, go to next step.

  10. Check for additional DTCs

    Refer to continuous DTCs recorded in step  1 . If any continuous DTCs were retrieved, go to diagnostic trouble code identification table for direction to appropriate test. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION  table. DO NOT clear any DTCs until all DTCs have been resolved. If no DTCs were retrieved, reconnect air bag system. Activate air bag system. See ACTIVATING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Clear all DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS.
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