Test No. 10: Automatic Lock Function Operates Even If Door Is Opened Within 30 Seconds After All Doors Are Unlocked Using Keyless Entry System

NOTE: Automatic lock function allows 30 seconds to open the door once the door is unlocked with the keyless remote or the door will be locked again.

Check that retaining screw on each door courtesy switch is tight to provide good ground connection. Door courtesy is located on pillar post at rear of each door. See Figure. If retaining screw for door courtesy switch is tight and good ground connection exists, go to next step. If retaining screw for door courtesy switch is loose, tighten retaining screw and recheck operation of automatic lock function. If automatic lock function still does not operate, go to next step. If automatic lock function operates, the problem was the loose retaining screw on door courtesy switch.
Check door courtesy switch. See DOOR COURTESY SWITCH under COMPONENT TESTS. If door courtesy switch is okay, go to next step. If door courtesy switch is defective, replace door courtesy switch and recheck operation of automatic lock function.
Check wiring harness and electrical connectors between each door courtesy switch and body Electronic Control Unit (ECU). See WIRING DIAGRAMS in POWER DOOR LOCKS & REMOTE KEYLESS ENTRY SYSTEMS - PRIUS article. Body ECU is located at driver's side of instrument panel on the fuse/relay box and contains an 18-pin and 20-pin electrical connector. 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 automatic lock 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 automatic lock function.
Replace body ECU with a known-good body ECU and recheck operation of automatic lock function. If automatic lock function operates properly, original body ECU was defective. If automatic lock function still does not operate properly, check wiring harness and electrical connectors between body ECU and each door courtesy switch for intermittent problem. See WIRING DIAGRAMS in POWER DOOR LOCKS & REMOTE KEYLESS ENTRY SYSTEMS - PRIUS article. Repair wiring harness or electrical connector as necessary.