Possible Causes
WARNING: This page is about a different car, the 2002 Lincoln LS. 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 Yellow wire (circuit No. 7-JA39), damaged Brown wire (circuit No.9-JA39) or damaged left side crash sensor.
- 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 . - 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 side crash sensor harness connection. If side crash sensor harness connector is connected to sensor correctly, go to next step. If side crash sensor harness connector is not properly connected to sensor, attach sensor harness connector correctly. Go to step 10 . - Check for open circuit
Turn ignition switch to OFF position. Access and disconnect RCM harness connector C310B. See RESTRAINTS CONTROL MODULE (RCM) under REMOVAL & INSTALLATION. See Figure . Disconnect left side crash sensor harness connector. Measure resistance of Yellow wire between RCM harness connector C310B, terminal No. 8 and left side crash sensor harness connector. If resistance is more than 10 k/ohms, repair open in Yellow wire. See WIRING DIAGRAMS . Go to step 10 . If resistance is less than 10 k/ohms, go to next step. - Check for open circuit
Measure resistance of Brown wire between RCM harness connector C310B, terminal No. 9 and left side crash sensor harness connector. If resistance is more than 10 k/ohms, repair open in Brown wire. Go to step 10 . If resistance is less than 10 k/ohms, go to next step. - Check for short to ground
Disconnect RCM connector C310A. Measure resistance between RCM harness connectors C310B, terminal No. 8 (Yellow wire) and C310A, terminal No. 21 (Black/Red wire, circuit No. 31-JA10A). If resistance is less than 10 k/ohms, repair short to ground in Yellow wire. Go to step 10 . If resistance is more than 10 k/ohms, go to next step. - Check for short to ground
Measure resistance between RCM harness connectors C310B, terminal No. 9 (Brown wire) and C310A, terminal No. 21 (Black/Red wire). If resistance is less than 10 k/ohms, repair short to ground in Brown wire. Go to step 10 . If resistance is more than 10 k/ohms, go to next step. - Check for short to voltage
Turn ignition switch to RUN position. Measure voltage between ground and RCM harness connectors C310B, terminal No. 8 (Yellow 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 Yellow wire. Go to step 10 . - Check for short to voltage
Measure voltage between ground and RCM harness connector C310B, terminal No. 9 (Brown 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 wire. Go to step 10 . - Check for intermittent fault
Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform on-demand self-test. If DTC U2017 was retrieved during on-demand self-test, go to step 2 . If DTC U2017 was not retrieved during on-demand self-test, check for cause of intermittent communication fault. Attempt to recreate fault by flexing wire harness and cycling ignition switch frequently. Repair any intermittent problems found. Go to next step. - 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.