Possible Causes
WARNING: This page is about a different car, the 2004 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.
A left seat belt pretensioner out of range resistance fault can be caused by damaged wiring, terminals or connectors, faulty seat belt pretensioner or faulty RCM.
- Check for hard or intermittent DTC
Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to RUN position. Retrieve and record any continuous DTCs. See RETRIEVING FAULT CODES under DIAGNOSTICS. Perform on-demand self-test. See ON-DEMAND SELF-TEST under DIAGNOSTICS. If DTC B1877 or B1885 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1877 or B1885 was not retrieved, fault is intermittent. Go to step 5 . - Check left seat belt pretensioner resistance
Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Using scan tool, select PID/Data Monitor and Record. Select PID D-PRTNR. If resistance is more than 3.2 ohms, go to next step. If resistance is less than 1.7 ohms, go to step 4 . If resistance is 1.7-3.2 ohms, replace RCM. See RESTRAINTS CONTROL MODULE (RCM) under REMOVAL & INSTALLATION. Go to step 6 . - Check left pretensioner circuits for high resistance
Turn ignition switch to OFF position. Disconnect left seat belt pretensioner harness connector C323. Disconnect RCM harness connector C310B. Measure resistance between harness side of RCM connector C310B, terminal No. 24 and harness side of left seat belt pretensioner harness connector C323, terminal No. 1 (Light Green/Red wire, circuit No. 1079). See Figure & Fig 1 . Measure resistance between harness side of RCM connector C310B, terminal No. 23 and harness side of left seat belt pretensioner harness connector C323, terminal No. 2 (Light Green/Black wire, circuit No. 1080). If resistance is less than 0.5 ohm, replace left seat belt pretensioner. See SEAT BELT PRETENSIONER under REMOVAL & INSTALLATION. Go to step 6 . If resistance is more than 0.5 ohm, repair high resistance in appropriate wire. See WIRING DIAGRAMS . Go to step 6 . - Check left pretensioner circuits for low resistance
Turn ignition switch to OFF position. Disconnect left seat belt pretensioner harness connector C323. Disconnect RCM harness connector C310B. Measure resistance between harness side of left seat belt pretensioner harness connector C323, terminal No. 1 (Light Green/Red wire, circuit No. 1079) and No. 2 (Light Green/Black wire, circuit No. 1080). See Fig 1 . If resistance is more than 10 k/ohms, replace left seat belt pretensioner. See SEAT BELT PRETENSIONER under REMOVAL & INSTALLATION. Go to step 6 . If resistance is less than 10 k/ohms, repair low resistance in appropriate wire. See WIRING DIAGRAMS . Go to step 6 . - Check for intermittent fault
Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform on-demand self-test. If DTC B1877 or B1885 was retrieved during on-demand self-test, check for cause of intermittent faults in Light Green/Red and Light Green/Black wires. Repair any intermittent faults found. If intermittent faults are found and corrected, go to next step. If intermittent faults are not found, go to step 2 . If DTC B1877 or B1885 was not retrieved during on-demand self-test, 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 continuous 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.