Test No. 28: Lock Or Unlock Function Does Not Operate
- Check door key lock and unlock switch on driver's side front door, passenger's side front door and back (rear liftgate) 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 door key lock and unlock switch and recheck operation of lock and unlock function.
- Check wiring harness and electrical connectors between body ground and each door key lock and unlock switch, and between body Electronic Control Unit (ECU) and each door key lock and unlock switch. See WIRING DIAGRAMS in POWER DOOR LOCKS - TRUCKS (EXCEPT SEQUOIA) article. Body ECU may also be referred to as integration relay. Body ECU is located at driver's side of instrument panel on the fuse/relay box. See Figure. Electrical connector I13 (7-pin or 25-pin) and electrical connector I16 (18-pin) are located at body ECU and a 12-pin electrical connector is located at rear of body ECU. See Figure. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary and recheck operation of lock and unlock function.
- Check door unlock detection switch on the driver's side front door and passenger's side front door. See DOOR UNLOCK DETECTION SWITCH under COMPONENT TESTS. If door unlock detection switch is okay, go to next step. If door unlock detection switch is defective, replace door lock assembly and recheck operation of lock and unlock function.
- Check wiring harness and electrical connectors between body ground and door unlock detection switch, and between door unlock detection switch and body ECU. See WIRING DIAGRAMS in KEYLESS ENTRY SYSTEMS - SIENNA article. If wiring harness or electrical connector is defective, repair as necessary and recheck operation of lock and unlock function.
- 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 operation of lock and unlock function.
- Replace body ECU with a known-good body ECU and recheck operation of lock and unlock function. If lock and unlock function operates properly, original body ECU was defective. If lock and unlock function still does not operate properly, check wiring harness and electrical connectors for body ECU for an intermittent problem. See WIRING DIAGRAMS in KEYLESS ENTRY SYSTEMS - SIENNA article. Repair wiring harness or electrical connector as necessary.