Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
- Remove ECU-B fuse and check continuity across fuse blades. ECU-B fuse is located in instrument panel fuse block under left side of instrument panel. If fuse is faulty, go to step 4. If fuse is okay, reinstall fuse and go to next step.
- Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Reconnect negative battery cable. Turn ignition switch to ON position. Measure voltage between ground and harness side of air bag sensor assembly connector C5, terminal No. 3 (circuit LA, Blue/Black wire). See Fig 1. If 10-14 volts is not present, repair AIR BAG warning light bulb or circuit. If 10-14 volts is present, go to next step.
- Turn ignition switch to LOCK position. Disconnect negative battery cable. Reconnect air bag sensor assembly connectors. Leave air bag modules, pretensioners and front air bag sensors disconnected. Reconnect negative battery cable and wait at least 2 seconds. Turn ignition switch to ON position. If AIR BAG warning light illuminates, system operation is normal. If AIR BAG warning light does not come on, check for poor connection at air bag sensor assembly connector C5, terminal No. 3 (Blue/Black wire). If connection is okay, replace air bag sensor assembly.
- Recheck ECU-B fuse. If fuse is blown, check harness between ECU-B fuse and AIR BAG warning light. If fuse is okay, check for intermittent fault. See AIR BAG WARNING LIGHT INTERMITTENT .