Test No. 3: Power Door Locks May Not Be Locked Or Unlocked When Using Power Door Lock Control Switch

Check door lock control switch on passenger's side front door. See DOOR LOCK CONTROL SWITCH under COMPONENT TESTS. If door lock control switch is okay, go to next step. If door lock control switch is defective, replace door lock control switch and recheck power door lock operation.
Check wiring harness and electrical connectors between door lock control switch on passenger's side front door 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 power door lock operation.
Check multiplex control system to see if Diagnostic Trouble Code (DTC) B1222 (Toyota hand-held tester) or DTC No. 22 (open door indicator light) exists. See MULTIPLEX CONTROL SYSTEMS - PRIUS article. If DTC B1222 or DTC No. 22 does not exist, go to next step. If DTC B1222 or DTC No. 22 exists, go to step 6.
Check power window master switch. See POWER WINDOW MASTER SWITCH under COMPONENT TESTS. If power window master switch is okay, go to next step. If power window master switch is defective, replace power window master switch and recheck power door lock operation.
Check wiring harness and electrical connectors for Yellow wire between power window master switch and body ECU. See WIRING DIAGRAMS in POWER DOOR LOCKS & REMOTE KEYLESS ENTRY SYSTEMS - PRIUS article. 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 power door lock operation.
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 power door lock operation.
Replace body ECU with a known-good body ECU and recheck power door lock operation. If power door lock operates properly, original body ECU was defective. If power door lock still do not operate properly, check wiring harness and electrical connectors for body ECU and power door locks for intermittent problem. See WIRING DIAGRAMS in POWER DOOR LOCKS & REMOTE KEYLESS ENTRY SYSTEMS - PRIUS article.