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Test No. 7: Lock Or Unlock Function Does Not Operate

  1. Check door key lock and unlock switch for driver's door and passenger's door. See DOOR KEY LOCK & UNLOCK SWITCH  under COMPONENT TESTS. If door key lock and unlock switch is okay, go to next step. If door key lock and unlock switch is defective, replace switch and recheck keyless entry system operation.
  2. Check wiring harness and electrical connectors between door key lock and unlock switch and body Electronic Control Unit (ECU). See WIRING DIAGRAMS in KEYLESS ENTRY SYSTEMS - CELICA article. Body ECU is located on instrument panel junction block and contains 12-pin, 22-pin and 25 pin electrical connectors. See Figure. 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 keyless entry system operation.
  3. Check door unlock detection switch on driver's door and passenger's door. See DOOR UNLOCK DETECTION SWITCH  under COMPONENT TESTS. If door unlock detection switches are okay, go to next step. If any door unlock detection switch is defective, replace door unlock detection switch and recheck keyless entry system operation.
  4. Check wiring harness and electrical connectors between door unlock detection switch on driver's door and passenger's door and body ECU. See WIRING DIAGRAMS in KEYLESS ENTRY SYSTEMS - CELICA article. 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 keyless entry system 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 keyless entry system operation.
  6. Replace body ECU with a known-good body ECU and recheck keyless entry system operation. If keyless entry system operates properly, original body ECU was defective. If keyless entry system still does not operate properly, check wiring harness and electrical connectors for body ECU, door unlock detection switches and door key lock and unlock switches for intermittent problem. See WIRING DIAGRAMS in KEYLESS ENTRY SYSTEMS - CELICA article. Repair wiring harness or electrical connector as necessary.
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