Diagnostic Procedure
WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.
- Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Ensure seat belt buckle switch is disconnected.
- Measure resistance between ground and air bag sensor assembly connector A23, terminals No. 19 (circuit LBE+, White wire). See Figure. If resistance is more than one megohm, go to next step. If resistance is less than one megohm, repair or replace wire harness between seat belt buckle switch and air bag sensor assembly.
- Deactivate link system. See LINK SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Reconnect negative battery cable. Turn ignition switch to ACC or ON position. Measure voltage between ground and air bag sensor assembly connector A23, terminals No. 19 (circuit LBE+, White wire). If voltage is less than one volt, go to next step. If voltage is more than one volt, repair or replace wire harness between seat belt buckle switch and air bag sensor assembly.
- Reconnect seat belt buckle switch connector. Ensure seat belt is not buckled. Measure resistance between ground and air bag sensor assembly connector A23, terminals No. 19 (circuit LBE+, White wire). If resistance is 1.0-1.6 k/ohms, go to next step. If resistance is not 1.0-1.6 k/ohms, replace front seat inner seat belt (buckle assembly).
- Buckle front belt. Measure resistance between ground and air bag sensor assembly connector A23, terminals No. 19 (circuit LBE+, White wire). If resistance is 100-500 ohms, go to next step. If resistance is not 100-500 ohms, replace front seat inner seat belt (buckle assembly).
- Ensure negative battery cable is disconnected. Reconnect air bag sensor assembly connector A23. Connect negative battery cable. Wait at least 2 seconds. Turn ignition switch to ACC or ON position. Wait at least 20 seconds. Clear DTCs. See CLEARING CODES under DIAGNOSTICS. Turn ignition switch to LOCK position. Wait at least 20 seconds. Turn ignition switch to ON position. Wait at least 20 seconds. Retrieve DTCs. See RETRIEVING CODES under DIAGNOSTICS. If DTC 27/B0126 or B0127 is displayed, replace air bag sensor assembly. If DTC 27/B0126 or B0127 is not displayed, system is functioning properly at this time. Check for intermittent fault. See AIR BAG WARNING LIGHT INTERMITTENT .