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Home >> Ford >> 2000 >> Excursion 7.3 F, 4WD >> Repair and Diagnosis (Single Page) >> Restraints >> Air Bag, SRS >> Supplemental Inflatable Restraint System - Excursion & Super Duty >> Diagnostic Tests >> Test M: Driver Air Bag Low Resistance (DTC B1934) >> Possible Causes

Possible Causes

Driver-side air bag low resistance could be caused by short circuit in clockspring windings, short circuit in wiring harness or low resistance in air bag module.

  1. Check for hard or intermittent DTC

    Ensure ignition is off. Connect scan tool to DLC. See USING SCAN TOOL  under DIAGNOSTICS. 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 B1934 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1934 was not retrieved, fault is intermittent. Go to step  5.
  2. Check driver-side air bag

    Turn ignition off. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Turn ignition switch to RUN position. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC B1934 is retrieved, go to next step. If DTC B1934 is not retrieved, replace driver-side air bag module. See DRIVER-SIDE AIR BAG MODULE  under REMOVAL & INSTALLATION. Go to step  6.
    NOTE: By disconnecting air bag simulator, driver-side air bag module circuit will be measured in series with high resistance dummy squib inside ECS module.
  3. Check driver-side air bag circuit

    Turn ignition off. Disconnect driver-side air bag simulator. Zero ohmmeter. Measure resistance between Gray/Orange and Gray/White wires of upper clockspring connector. If resistance is less than 10 k/ohms, go to next step. If resistance is more than 10 k/ohms, replace ECS module. See ELECTRONIC CRASH SENSOR  under REMOVAL & INSTALLATION. Go to step  6.
  4. Check air bag clockspring

    Disconnect lower clockspring connector located on steering column side of clockspring. Zero ohmmeter. Measure resistance between gray/Orange and Gray/White wires of lower clockspring connector. If resistance is less 10 k/ohms, repair Light Green and/or Gray/White wire as necessary. Go to step  6. If resistance is more than 10 k/ohms, replace clockspring assembly. See CLOCKSPRING  under REMOVAL & INSTALLATION. Go to step  6.
  5. Check for intermittent fault

    Refer to continuous DTCs recorded in step  1. If DTC retrieved in step  1 was an intermittent fault, check for cause of intermittent low resistance on Gray/Orange wire, Gray/White wire and clockspring. Attempt to recreate fault by driving vehicle, 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.
  6. 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. If no continuous DTCs were retrieved, reconnect air bag system. Activate air bag system. See ACTIVATING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Prove out system. Clear all DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS.