Diagnostic Procedure
WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.
- Turn ignition switch to LOCK position. Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Connect negative battery cable. Wait at least 2 seconds. Turn ignition switch to ON position. Wait at least 60 seconds. Clear DTCs. Turn ignition switch to LOCK position. Turn ignition switch to ON position. Wait at least 60 seconds. Retrieve DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES (DTCS) under DIAGNOSTICS. If DTC 35/B1653 is displayed, go to next step. If DTC 35/B1653 is not displayed, check for intermittent fault. See AIR BAG WARNING LIGHT INTERMITTENT .
- Turn ignition switch to LOCK position. Disconnect negative battery cable. and wait at least 90 seconds. Access air bag sensor assembly. See AIR BAG SENSOR ASSEMBLY under REMOVAL & INSTALLATION. Access seat position sensor. See SEAT POSITION SENSOR under REMOVAL & INSTALLATION. Ensure harness connectors are properly connected to seat position sensor and air bag sensor assembly. If connectors are properly connected, go to next step. If connectors are not properly connected, reconnect connector and go to step 1.
- Disconnect air bag center connector A30. Disconnect left front seat harness connector. Connect jumper wire between front seat harness connector terminals No. 2 (Brown/Red wire, circuit DSP+) and No. 4 (Orange wire, circuit DSP-). See Fig 1. Measure resistance between ground and harness side of air bag sensor assembly connector A30, terminals No. 9 and 17. See Figure. If resistance is less than one ohm, go to next step. If resistance is more than one ohm, repair or replace wiring harness between front seat harness connector and air bag sensor assembly. See WIRING DIAGRAMS .
- Remove jumper wire. Measure resistance between harness side of air bag sensor assembly connector A30, terminals No. 9 and 17. If resistance is more than one megohm, go to next step. If resistance is less than one megohm, repair or replace wiring harness between front seat harness connector and air bag sensor assembly.
- Connect negative battery cable. Wait at least 2 seconds. Turn ignition switch to ON position. Measure voltage between ground and harness side of air bag sensor assembly connector A30, terminals No. 9 and No. 17. If voltage is less than one volt, go to next step. If voltage is more than one volt, repair or replace wiring harness between front seat harness connector and air bag sensor assembly.
- Turn ignition switch to LOCK position. Disconnect negative battery cable. Wait at least 90 seconds. Measure resistance between ground and harness side of air bag sensor assembly connector A30, terminals No. 9 and No. 17. If resistance is more than one megohm, go to next step. If resistance is less than one megohm, repair or replace wiring harness between front seat harness connector and air bag sensor assembly.
- Connect air bag sensor assembly and seat position sensor connectors. Connect negative battery cable. Wait at least 2 seconds. Turn ignition switch to ON position. Wait at least 60 seconds. Clear DTCs. Turn ignition switch to LOCK position. Turn ignition switch to ON position. Wait at least 60 seconds. Retrieve DTCs. If DTC 35/B1653 is displayed, go to next step. If DTC 35/B1653 is not displayed, check for intermittent fault.
- Turn ignition switch to LOCK position. Disconnect negative battery cable. Wait at least 90 seconds. Replace seat position sensor. Connect negative battery cable. Wait at least 2 seconds. Turn ignition switch to ON position. Wait at least 60 seconds. Clear DTCs. Turn ignition switch to LOCK position. Turn ignition switch to ON position. Wait at least 60 seconds. Retrieve DTCs. If DTC 35/B1653 is displayed, air bag sensor assembly. If DTC 35/B1653 is not displayed, repair or replace wiring harness between front seat harness connector and air bag sensor assembly.