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Test No. 17: Keyless Entry System Operates But Buzzer Does Not Sound

  1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step  3.
  2. Connect hand-held tester to Data Link Connector (DLC) No. 3. See Figure. Using hand-held tester manufacturer's instructions, check operation of buzzer for keyless entry system while using the ACTIVE TEST. Buzzer for keyless entry system should operate while using the ACTIVE TEST. If buzzer for keyless entry system does not operate properly, remove hand-held tester. Go to next step. If buzzer for keyless entry system operates, remove hand-held tester. Go to step  5.
  3. Check buzzer for keyless entry system. See BUZZER FOR KEYLESS ENTRY SYSTEM  under COMPONENT TESTS. If buzzer for keyless entry system is okay, go to next step. If buzzer for keyless entry system is defective, replace buzzer and recheck buzzer operation.
  4. Check wiring harness and electrical connectors between buzzer for keyless entry system and body Electronic Control Unit (ECU), and between buzzer for keyless entry system and ground connection. See WIRING DIAGRAMS in POWER DOOR LOCKS & REMOTE KEYLESS ENTRY SYSTEMS - SEQUOIA article. Body ECU is located behind driver's side of instrument panel and contains 3 electrical connectors. See Figure. Buzzer for keyless entry system may also be referred to as wireless door lock control buzzer. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary and recheck buzzer operation.
  5. Check body ECU for proper voltage and input signals. See BODY ELECTRONIC CONTROL UNIT  under PIN VOLTAGE TESTS. If proper voltage and input signals exist, go to next step. If proper voltage and input signals do not exist, repair as necessary and recheck buzzer operation.
  6. Replace body ECU with a known-good body ECU and recheck buzzer operation. If buzzer operates properly, original body ECU was defective. If buzzer still does not operate properly, check wiring harness and electrical connectors for body ECU and buzzer for keyless entry system for an intermittent problem. See WIRING DIAGRAMS in POWER DOOR LOCKS & REMOTE KEYLESS ENTRY SYSTEMS - SEQUOIA article. Repair wiring harness or electrical connector as necessary.
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