Test Procedure
WARNING: This page is about a different car, the 2003 Lexus ES 300 and 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect the anti-theft warning ECU assembly connector. Measure the voltage between terminal SH (T6-24) of the anti-theft warning ECU assembly connector and body ground. See Fig 1. If the voltage is 10-14 volts, go to the next step. If the voltage is not 10-14 volts, repair or replace the harness and connector as necessary.
- Connect the positive (+) lead to terminal No. 1 of the anti-theft horn connector and the negative (-) lead to ground. See Fig 2. If the anti-theft horn blows, go to the next step. If the anti-theft horn does not blow, replace the security horn assembly.
- Check the continuity between terminal SH- (T6-25) of the anti-theft ECU connector and terminal No. 1 of the security horn connector. See Fig 2 and Fig 3 . If continuity exists, check and replace the anti-theft warning ECU assembly. If continuity does not exist, repair or replace the harness and connector as necessary.