Body Control Systems: Diagnosis Lexus RX I

TROUBLE SHOOTING

Note. Prior to trouble shooting, ensure no problems exist in multiplex communications. If problems exist, repair multiplex control system before trouble shooting. See appropriate MULTIPLEX CONTROL SYSTEMS article.

Inspect for mechanical or electrical damage. Repair or replace as necessary. If components are okay, repair by symptom. See appropriate SYMPTOM INDEX table under SYSTEM TESTS .

TEST NO. 1: ANTI-THEFT HORN CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Connect a jumper wire between DLC1 connector terminals E1 and Tc. (Scheme 2) Using scan tool, operate anti-theft horn in ACTIVE TEST. If anti-theft horn does not operate, go to next step. If anti-theft horn operates, go to step 3.
2. Check anti-theft horn. See «ANTI-THEFT HORN»(ref-8993-S03254834822000093000000) under COMPONENT TESTS. Replace anti-theft horn as necessary. Retest system operation. If anti-theft horn is okay, go to next step.
3. Check circuits for faults between anti-theft horn and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000). Repair or replace as necessary. If circuits are okay, perform «TEST NO. 34: STANDARD HORN CIRCUIT»(ref-8993-S19047014392000093000000).

Scheme 2

TEST NO. 2: ANTI-THEFT INDICATOR CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Connect a jumper wire between DLC1 connector terminals E1 and Tc. (Scheme 2) Using scan tool, operate anti-theft indicator in ACTIVE TEST. If anti-theft indicator does not operate, go to next step. If anti-theft indicator operates, go to step 3.
2. Check anti-theft indicator. See «ANTI-THEFT INDICATOR»(ref-8993-S06090864372000093000000) under COMPONENT TESTS. Replace anti-theft indicator as necessary. Retest system operation. If anti-theft indicator is okay, go to next step.
3. Check circuits for faults between anti-theft indicator, body control ECU and ground. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000). Repair or replace as necessary. If circuits are okay, perform «TEST NO. 3: BACK DOOR KEY LOCK & UNLOCK SWITCH CIRCUIT»(ref-8993-S26744784622000093000000).

TEST NO. 3: BACK DOOR KEY LOCK & UNLOCK SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check back door key lock and unlock switch using DATA LIST. If back door key lock and unlock switch is faulty, go to next step. If back door key lock and unlock switch is okay, go to step 3 .
2. Check back door key lock and unlock switch. See «DOOR KEY LOCK & UNLOCK SWITCH»(ref-8993-S10108139112000093000000) under COMPONENT TESTS. Replace switch as necessary. Retest system operation. If switch is okay, go to next step.
3. Check circuits for faults between back door key lock and unlock switch and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 4: DRIVER'S DOOR COURTESY LIGHT & COURTESY SWITCH CIRCUIT»(ref-8993-S19797935642000093000000) .

TEST NO. 4: DRIVER'S DOOR COURTESY LIGHT & COURTESY SWITCH CIRCUIT

1. Open and close driver door while observing driver door courtesy light operation. If driver door courtesy light does not illuminate when door is opened and go out when door is closed, go to next step. If driver door courtesy light illuminates when door is opened and goes out when door is closed, go to step 4 .
2. Check driver door courtesy light. See «DOOR COURTESY LIGHT»(ref-8993-S27160577962000093000000) under COMPONENT TESTS. Replace driver door courtesy light as necessary. Retest system operation. If driver door courtesy light is okay, go to next step.
3. Check driver door courtesy switch. See «DOOR COURTESY SWITCH»(ref-8993-S00454344772000093000000) under COMPONENT TESTS. Replace driver door courtesy switch as necessary. Retest system operation. If driver door courtesy switch is okay, go to next step.
4. Check circuits for faults between driver door courtesy light, driver door courtesy switch and driver door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 7: DRIVER'S DOOR UNLOCK DETECTION SWITCH CIRCUIT»(ref-8993-S36516693342000093000000) .

TEST NO. 5: DRIVER DOOR KEY LOCK & UNLOCK SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check for DTC B1222. If DTC B1222 is retrieved, go to next step. If DTC B1222 is not retrieved, go to step 3 .
2. Check driver door key lock and unlock switch. See «DOOR KEY LOCK & UNLOCK SWITCH»(ref-8993-S10108139112000093000000) under COMPONENT TESTS. Replace switch as necessary. Retest system operation. If switch is okay, go to next step.
3. Check circuits for faults between driver door key lock and unlock switch and driver door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 22: PASSENGER'S DOOR KEY LOCK & UNLOCK SWITCH CIRCUIT»(ref-8993-S31421300352000093000000) .

TEST NO. 6: DRIVER DOOR LOCK MOTOR CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, operate driver door lock motor in ACTIVE TEST. If door lock motor does not operate, go to next step. If door lock motor operates properly, go to step 3 .
2. Check driver door lock motor. See «DOOR LOCK MOTOR»(ref-8993-S24761154852000093000000) under COMPONENT TESTS. Replace door lock motor as necessary. Retest system operation. If door lock motor is okay, go to next step.
3. Check circuits for faults between driver door lock motor and driver door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 7: DRIVER'S DOOR UNLOCK DETECTION SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check driver door unlock detection switch using DATA LIST. If door unlock detection switch is faulty, go to next step. If door unlock detection switch is okay, go to step 3 .
2. Check driver door unlock detection switch. See «DOOR UNLOCK DETECTION SWITCH»(ref-8993-S20635023352000093000000) under COMPONENT TESTS. Replace door unlock detection switch (motor assembly) as necessary. Retest system operation. If switch is okay, go to next step.
3. Check circuits for faults between driver door unlock detection switch and driver door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 10: ENGINE HOOD COURTESY SWITCH CIRCUIT»(ref-8993-S31676964002000093000000) .

TEST NO. 8: DRIVER SEAT BELT BUCKLE SWITCH

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check driver seat belt buckle switch using DATA LIST. If driver seat belt buckle switch is faulty, go to next step. If driver seat belt buckle switch is okay, go to step 3 .
2. Check driver seat belt buckle switch. See «SEAT BELT BUCKLE SWITCH»(ref-8993-S21856081062000093000000) under COMPONENT TESTS. Replace driver seat belt buckle switch as necessary. Retest system operation. If driver seat belt buckle switch is okay, go to next step.
3. Check circuits for faults between driver seat belt buckle switch, body control ECU and ground. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TEST.

TEST NO. 9: ECU POWER SOURCE CIRCUIT

1. Check condition of RR WIP, RADIO NO. 2, P FR DOOR, and GAUGE fuses located in instrument panel junction block, under left side of instrument panel. If fuses are okay, go to next step. If fuse(s) are faulty, replace appropriate fuse and retest system operation.
2. Turn ignition on. Using a voltmeter, measure voltage between the following ECU connector terminals. see scheme 3 Connector B5, terminal No. 8 (WIG) and connector B5, terminal No. 9 (GND1). Connector B8, terminal No. 18 (ACC) and connector B5, terminal No. 9 (GND1). Connector B8, terminal No. 5 (IG) and connector B5, terminal No. 9 (GND1). Connector B5, terminal No. 8 (WIG) and connector B8, terminal No. 2 (GND2). Connector B8, terminal No. 18 (ACC) and connector B8, terminal No. 2 (GND2). Connector B8, terminal No. 5 (IG) and connector B8, terminal No. 2 (GND2). If voltages are not 10-14 volts, go to next step. If voltages are 10-14 volts, go to step 4.
3. Turn ignition off. Disconnect body control ECU connector (located under left side of instrument panel). Turn ignition on. Using a voltmeter, measure voltage between the following ECU connector terminals. Connector B8, terminal No. 4 (BSUB) and connector B5, terminal No. 9 (GND1). Connector B5, terminal No. 2 (BECU) and connector B5, terminal No. 9 (GND1). Connector B8, terminal No. 4 (BSUB) and connector B8, terminal No. 2 (GND2). Connector B5, terminal No. 2 (BECU) and connector B8, terminal No. 2 (GND2). If voltages are not 10-14 volts, go to next step. If voltages are 10-14 volts, go to step 4.
4. Check circuits for faults between body ground and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000). Repair or replace as necessary. If circuits are okay, check and repair circuits between body control ECU and battery. Retest system operation.

TEST NO. 10: ENGINE HOOD COURTESY SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check engine hood courtesy switch using DATA LIST. If engine hood courtesy switch is faulty, go to next step. If engine hood courtesy switch is okay, go to step 3
2. Check engine hood courtesy switch. See «ENGINE HOOD COURTESY SWITCH»(ref-8993-S05301659452000093000000) under COMPONENT TESTS. Replace engine hood courtesy switch as necessary. Retest system operation. If switch is okay, go to next step.
3. Check circuits for faults between engine hood courtesy switch and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 15: KEY UNLOCK WARNING SWITCH CIRCUIT»(ref-8993-S09549553642000093000000) .

TEST NO. 11: HAZARD SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, operate hazard switch in ACTIVE TEST. If hazard switch does not operate, go to next step. If hazard switch operates, go to step 3 .
2. Check hazard switch. See «HAZARD SWITCH»(ref-8993-S42757518192000093000000) under COMPONENT TESTS. Replace hazard switch as necessary. Retest system operation. If hazard switch is okay, go to next step.
3. Check circuits for faults between hazard switch and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 12: HEADLIGHT CONTROL SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check headlight control switch using DATA LIST. If headlight switch is faulty, go to next step. If headlight switch is okay, go to step 3 .
2. Check headlight control switch. See STEERING COLUMN SWITCHES article. Replace headlight control switch as necessary. Retest system operation. If headlight control switch is okay, go to next step.
3. Check circuits for faults between headlight control switch and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 19: LIGHT SENSOR CIRCUIT»(ref-8993-S35150549822000093000000) .

TEST NO. 13: HEADLIGHT RELAY CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, operate headlight relay in ACTIVE TEST. If headlight relay does not operate, go to next step. If headlight relay operates, go to step 3 .
2. Check headlight relay. See «HEADLIGHT RELAY»(ref-8993-S05469200222000093000000) under COMPONENT TESTS. Replace headlight relay as necessary. Retest system operation. If headlight relay is okay, go to next step.
3. Check circuits for faults between headlight relay, body control ECU and battery. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 14: ILLUMINATION CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, operate interior lights in ACTIVE TEST. If interior lights do not operate properly, go to next step. If interior lights operate properly, go to step 3 .
2. Using an ohmmeter, check continuity of bulb in question. Replace light as necessary and retest system operation. If light is okay, go to next step.
3. Check circuits for faults between interior lights, body control ECU and battery. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 15: KEY UNLOCK WARNING SWITCH CIRCUIT

1. Check key unlock warning switch. See STEERING COLUMN SWITCHES article. Replace switch as necessary. Retest system operation. If switch is okay, go to next step.
2. Check circuits for faults between key unlock warning switch and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 16: LEFT REAR DOOR COURTESY LIGHT & COURTESY SWITCH CIRCUIT»(ref-8993-S40104074842000093000000) .

TEST NO. 16: LEFT REAR DOOR COURTESY LIGHT & COURTESY SWITCH CIRCUIT

1. Open and close left rear door while observing left rear door courtesy light operation. If left rear door courtesy light does not illuminate when door is opened and go out when door is closed, go to next step. If left rear door courtesy light operates as specified, go to step 4 .
2. Check left rear door courtesy light. See «DOOR COURTESY LIGHT»(ref-8993-S27160577962000093000000) under COMPONENT TESTS. Replace left rear door courtesy light as necessary. Retest system operation. If left rear door courtesy light is okay, go to next step.
3. Check left rear door courtesy switch. See «DOOR COURTESY SWITCH»(ref-8993-S00454344772000093000000) under COMPONENT TESTS. Replace left rear door courtesy switch as necessary. Retest system operation. If left rear door courtesy switch is okay, go to next step.
4. Check circuits for faults between left rear door courtesy light, left rear door courtesy switch and left rear door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 18: LEFT REAR DOOR UNLOCK DETECTION SWITCH CIRCUIT»(ref-8993-S19266266072000093000000) .

TEST NO. 17: LEFT REAR DOOR LOCK MOTOR CIRCUIT

1. Check left rear door lock motor. See «DOOR LOCK MOTOR»(ref-8993-S24761154852000093000000) under COMPONENT TESTS. Replace door lock motor as necessary. Retest system operation. If door lock motor is okay, go to next step.
2. Check circuits for faults between left rear door lock motor and left rear door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TEST.

TEST NO. 18 LEFT REAR DOOR UNLOCK DETECTION SWITCH CIRCUIT

1. Check left rear door unlock detection switch. See «DOOR UNLOCK DETECTION SWITCH»(ref-8993-S20635023352000093000000) under COMPONENT TESTS. Replace door unlock detection switch (motor assembly) as necessary. Retest system operation. If switch is okay, go to next step.
2. Check circuits for faults between left rear door unlock detection switch and left rear door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 21: PASSENGER'S DOOR COURTESY LIGHT & COURTESY SWITCH CIRCUIT»(ref-8993-S04047257222000093000000) .

TEST NO. 19: LIGHT SENSOR CIRCUIT

Note. LEXUS scan tool must be used for this test.

1. Using scan tool, check light sensor output frequency. If light sensor output frequency is 47-1200 Hertz, go to next step. If light sensor output frequency is not 47-1200 Hertz, replace light sensor and retest system operation.
2. Check circuits for faults between light sensor and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, check body control ECU pin voltages. See «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS. Replace as necessary and retest system operation.

TEST NO. 20: PARKING BRAKE SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check parking brake switch using DATA LIST. If parking brake switch is faulty, go to next step. If parking brake switch is okay, go to step 3 .
2. Check parking brake switch. See «PARKING BRAKE SWITCH»(ref-8993-S34894723862000093000000) under COMPONENT TESTS. Replace parking brake switch as necessary. Retest system operation. If parking brake switch is okay, go to next step.
3. Check circuits for faults between parking brake switch and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TEST.

TEST NO. 21: PASSENGER'S DOOR COURTESY LIGHT & COURTESY SWITCH CIRCUIT

1. Open and close passenger door while observing passenger door courtesy light operation. If passenger door courtesy light does not illuminate when door is opened and go out when door is closed, go to next step. If passenger door courtesy light operates as specified, go to step 4 .
2. Check passenger door courtesy light. See «DOOR COURTESY LIGHT»(ref-8993-S27160577962000093000000) under COMPONENT TESTS. Replace passenger door courtesy light as necessary. Retest system operation. If passenger door courtesy light is okay, go to next step.
3. Check passenger door courtesy switch. See «DOOR COURTESY SWITCH»(ref-8993-S00454344772000093000000) under COMPONENT TESTS. Replace passenger door courtesy switch as necessary. Retest system operation. If passenger door courtesy switch is okay, go to next step.
4. Check circuits for faults between passenger door courtesy light, passenger door courtesy switch and passenger door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 25: PASSENGER'S DOOR UNLOCK DETECTION SWITCH CIRCUIT»(ref-8993-S02976978872000093000000) .

TEST NO. 22: PASSENGER'S DOOR KEY LOCK & UNLOCK SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check for DTC B1224. If DTC B1224 is retrieved, go to next step. If DTC B1224 is not retrieved, go to step 3 .
2. Check passenger door key lock and unlock switch. See «DOOR KEY LOCK & UNLOCK SWITCH»(ref-8993-S10108139112000093000000) under COMPONENT TESTS. Replace switch as necessary. Retest system operation. If switch is okay, go to next step.
3. Check circuits for faults between passenger door key lock and unlock switch and passenger door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 23: PASSENGER DOOR LOCK CONTROL SWITCH CIRCUIT

Passenger door lock control switch is part of passenger door ECU. To check passenger door ECU, go to appropriate wiring diagram in POWER DOOR LOCKS, TRUNK LID & FUEL DOOR RELEASE article.

TEST NO. 24: PASSENGER DOOR LOCK MOTOR CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, operate passenger door lock motor in ACTIVE TEST. If door lock motor does not operate, go to next step. If door lock motor operates properly, go to step 3 .
2. Check passenger door lock motor. See «DOOR LOCK MOTOR»(ref-8993-S24761154852000093000000) under COMPONENT TESTS. Replace door lock motor as necessary. Retest system operation. If door lock motor is okay, go to next step.
3. Check circuits for faults between passenger door lock motor and passenger door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 25: PASSENGER'S DOOR UNLOCK DETECTION SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check passenger door unlock detection switch using DATA LIST. If door unlock detection switch is faulty, go to next step. If door unlock detection switch is okay, go to step 3 .
2. Check passenger door unlock detection switch. See «DOOR UNLOCK DETECTION SWITCH»(ref-8993-S20635023352000093000000) under COMPONENT TESTS. Replace door unlock detection switch (motor assembly) as necessary. Retest system operation. If switch is okay, go to next step.
3. Check circuits for faults between passenger door unlock detection switch and passenger door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 31: RIGHT REAR DOOR COURTESY LIGHT & COURTESY SWITCH CIRCUIT»(ref-8993-S19604257532000093000000) .

TEST NO. 26: POWER WINDOW MASTER SWITCH/DRIVER DOOR LOCK CONTROL SWITCH CIRCUIT

Power window master switch/driver door lock control switch is part of driver door ECU. To check driver door ECU, go to appropriate wiring diagram in POWER DOOR LOCKS, TRUNK LID & FUEL DOOR RELEASE article.

TEST NO. 27: REAR INTERIOR LIGHT & BACK DOOR COURTESY SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check back door courtesy switch using DATA LIST. If back door courtesy switch is faulty, go to next step. If back door courtesy switch is okay, go to step 3 .
2. Check back door courtesy switch. See «BACK DOOR COURTESY SWITCH»(ref-8993-S24841199342000093000000) under COMPONENT TESTS. Replace back door courtesy switch as necessary. Retest system operation. If switch is okay, go to next step.
3. Check circuits for faults between back door courtesy switch and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 28: REAR WASHER MOTOR CIRCUIT

Disconnect washer motor 3-pin connector. Using a voltmeter, measure voltage between terminal No. 2 (Blue/White wire) and ground. See WIRING DIAGRAMS . If battery voltage is present, check washer motor. See appropriate WIPER/WASHER SYSTEMS article. Replace washer motor as necessary. Retest system operation. If battery voltage is not present, check wire harness, connectors and 10-amp WASHER fuse located in instrument panel junction block, under left side of instrument panel. Repair or replace as necessary. Retest system operation.

TEST NO. 29: REAR WIPER MOTOR CIRCUIT

Rear wiper motor circuit testing information is not available from manufacturer. To check rear wiper motor, see appropriate WIPER/WASHER SYSTEMS article.

TEST NO. 30: RHEOSTAT LIGHT CONTROL CIRCUIT

Rheostat light control circuit testing information is not available from manufacturer. To check rheostat light control, go to appropriate INSTRUMENT PANELS article.

TEST NO. 31: RIGHT REAR DOOR COURTESY LIGHT & COURTESY SWITCH CIRCUIT

1. Open and close right rear door while observing right rear door courtesy light operation. If right rear door courtesy light does not illuminate when door is opened and go out when door is closed, go to next step. If right rear door courtesy light illuminates when door is opened and goes out when door is closed, go to step 4 .
2. Check right rear door courtesy light. See «DOOR COURTESY LIGHT»(ref-8993-S27160577962000093000000) under COMPONENT TESTS. Replace right rear door courtesy light as necessary. Retest system operation. If right rear door courtesy light is okay, go to next step.
3. Check right rear door courtesy switch. See «DOOR COURTESY SWITCH»(ref-8993-S00454344772000093000000) under COMPONENT TESTS. Replace right rear door courtesy switch as necessary. Retest system operation. If right rear door courtesy switch is okay, go to next step.
4. Check circuits for faults between right rear door courtesy light, right rear door courtesy switch and right rear door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform «TEST NO. 33: RIGHT REAR DOOR UNLOCK DETECTION SWITCH CIRCUIT»(ref-8993-S35369721182000093000000) .

TEST NO. 32: RIGHT REAR DOOR LOCK MOTOR CIRCUIT

1. Check right rear door lock motor. See «DOOR LOCK MOTOR»(ref-8993-S24761154852000093000000) under COMPONENT TESTS. Replace door lock motor as necessary. Retest system operation. If door lock motor is okay, go to next step.
2. Check circuits for faults between right rear door lock motor and right rear door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 33: RIGHT REAR DOOR UNLOCK DETECTION SWITCH CIRCUIT

1. Check right rear door unlock detection switch. See «DOOR UNLOCK DETECTION SWITCH»(ref-8993-S20635023352000093000000) under COMPONENT TESTS. Replace door unlock detection switch (motor assembly) as necessary. Retest system operation. If switch is okay, go to next step.
2. Check circuits for faults between right rear door unlock detection switch and right rear door ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TEST»(ref-8993-S02647152582000093000000) under COMPONENT TEST.

TEST NO. 34: STANDARD HORN CIRCUIT

1. Check standard horn. See «STANDARD HORN»(ref-8993-S27916983432000093000000) under COMPONENT TESTS. Replace standard horn as necessary. Retest system operation. If standard horn is okay, go to next step.
2. Check circuits for faults between horn relay, body control ECU and battery. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TEST»(ref-8993-S02647152582000093000000) under COMPONENT TEST.

TEST NO. 35: STOPLIGHT SWITCH CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, check stoplight switch using DATA LIST. If stoplight switch is faulty, go to next step. If stoplight switch is okay, go to step 3 .
2. Check stoplight switch. See «STOPLIGHT SWITCH»(ref-8993-S13263099572000093000000) under COMPONENT TESTS. Replace stoplight switch as necessary. Retest system operation. If stoplight switch is okay, go to next step.
3. Check circuits for faults between stoplight switch, body control ECU and battery. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 36: TAILLIGHT RELAY CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, operate taillight relay in ACTIVE TEST. If taillight relay does not operate , go to next step. If taillight relay operates, go to step 3 .
2. Check taillight relay. See «TAILLIGHT RELAY»(ref-8993-S30822118562000093000000) under COMPONENT TESTS. Replace taillight relay as necessary. Retest system operation. If taillight relay is okay, go to next step.
3. Check circuits for faults between taillight relay, body control ECU and battery. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 37: WIPER/WASHER SWITCH CIRCUIT

Wiper/washer switch circuit testing information for rear wiper system is not available from manufacturer. To check wiper/washer switch, go to appropriate WIPER/WASHER SYSTEMS article.

TEST NO. 38: WIRELESS DOOR LOCK BUZZER CIRCUIT

Note. If LEXUS scan tool is available, start test from step 1 . If this scan tool is not available, start test from step 2 .

1. Using scan tool, operate wireless door lock buzzer in ACTIVE TEST. If wireless door lock buzzer does not operate, go to next step. If wireless door lock buzzer operates, go to step 3 .
2. Check wireless door lock buzzer. See «WIRELESS DOOR LOCK BUZZER»(ref-8993-S42535714192000093000000) under COMPONENT TESTS. Replace wireless door lock buzzer as necessary. Retest system operation. If buzzer is okay, go to next step.
3. Check circuits for faults between wireless door lock buzzer and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary. If circuits are okay, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.

TEST NO. 39: WIRELESS DOOR LOCK TUNER CIRCUIT

1. Using scan tool, check for DTC 42. If DTC 42 is not retrieved, go to next step. If DTC 42 is retrieved, check for faults in Blue wire between wireless door lock tuner and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace as necessary.
2. Check circuits for faults between wireless door lock tuner and body control ECU. See «WIRING DIAGRAMS»(ref-8993-S32970494742000093000000) . Repair or replace circuits as necessary. If circuits are okay, go to next step.
3. Replace original wireless door lock tuner with known-good unit and ensure it recovers normally. If tuner recovers normally, original wireless door lock tuner failed. If tuner does not recover normally, perform appropriate pin voltage test in «BODY CONTROL ECU PIN VOLTAGE TESTS»(ref-8993-S02647152582000093000000) under COMPONENT TESTS.