Lighting System (Interior) (Diagnostics & Circuit Tests): Overview Lexus CT I

SYSTEM DESCRIPTION

1. ILLUMINATED ENTRY SYSTEM The illuminated entry system has the following control functions: Control Outline Lights that Operate Actuation Area-linked When a registered key enters any actuation area around the doors, the lights that operate turn on. Power Switch Illumination Front Interior Lights Rear Interior Light Footwell Lights When a registered key leaves all of actuation areas around the doors, the lights that operate turn off. Power Switch Illumination Front Interior Lights Rear Interior Light Footwell Lights Door Lock/Unlock-linked When any door is unlocked, the lights that operate turn on. Power Switch Illumination Front Interior Lights Rear Interior Light Footwell Lights When all doors are locked, the lights that operate turn off. Power Switch Illumination Front Interior Lights Rear Interior Light Footwell Lights Door Open/Close-linked When any door is opened, the lights that operate turn on. Power Switch Illumination Front Interior Lights Rear Interior Light Footwell Lights When all doors are closed, the lights that operate turn off. Power Switch-linked When the power switch is turned from on (ACC or IG) to off, the lights that operate turn on. Power Switch Illumination Front Interior Lights Rear Interior Light When the power switch is turned from off to on (ACC or IG) the lights that operate turn off. Power Switch Illumination Front Interior Lights Rear Interior Light When the power switch is turned from off to on (IG) the lights that operate turn on. Footwell Lights Delay When approximately 15 seconds elapse after any of the following conditions is met, the lights that operate turn off: An actuation area-linked function is used. The door unlock-linked function is active. Any door is opened and then all doors are closed when the power switch is off. Power Switch Illumination Front Interior Lights Rear Interior Light Footwell Lights Battery Saving When no changes occur in the condition of the doors for 20 minutes and a key is not in the actuation area, the lights that operate turn off. Power Switch Illumination Front Interior Lights Rear Interior Light Footwell Lights

OPERATION CHECK

1. INSPECT INTERIOR LIGHT CONTROL OPERATION NOTE: Perform this inspection with the customize parameters at the initial settings. HINT: The interior light control illuminates the lights below. Power Switch Illumination Front Interior Lights Rear Interior Light The operation and conditions of this control are described below. Operation Condition Fade in and illuminate constantly Any door is opened when all doors are closed. Illuminate for 15 seconds, and then fade out When any of the following conditions is met, the lights illuminate for 15 seconds, and then fade out: The key enters any actuation area around the doors when the power switch is off and all doors are closed*1. Any door is unlocked when the power switch is off with all doors closed and locked. The power switch is turned from on (IG) to off when all doors are closed. All doors are closed after any door is opened and the power switch is off. Fade out immediately When any of the following conditions is met, the lights fade out immediately: The power switch is turned from off to on (ACC) when all doors are closed. All doors are locked when the power switch is off, all doors are closed and any door is unlocked. All doors are locked again when all doors are already closed and locked. Battery saving When no changes occur in the condition of the doors for 20 minutes and a key is not in the actuation area, the lights that operate turn off. HINT: *1: When the lights are on, if the key leaves all of actuation areas around the doors, after approximately 3 seconds, the lights fade out.
2. INSPECT FOOTWELL LIGHT CONTROL OPERATION NOTE: Perform this inspection with the customize parameters at the initial settings. HINT: The footwell light control illuminates the lights below. Footwell light LH Footwell light RH The operation and conditions of this control are described below. Operation Condition Fade in and illuminate constantly When either of the following conditions is met, the footwell light LH and footwell light RH fade in: Any door is opened when all doors are closed. The power switch is turned from off to on (IG). Illuminate for 15 seconds, and then fade out When any of the following conditions is met, the footwell light LH and foot light RH illuminate for 15 seconds and then fade out: Any door is unlocked when the power switch is off, all doors are closed and all doors are locked. The power switch is turned from on (IG) to off when all doors are closed. All doors are closed when any door is opened and the power switch is off. Fade out immediately All doors are locked when the power switch is off, all doors are closed and any door is unlocked.
3. INSPECT CENTER CONSOLE SPOT LIGHT CONTROL OPERATION NOTE: Perform this inspection with the customize parameters at the initial settings. HINT: The center console spot light control illuminates the light below. Center console spot light The operation and conditions of this control are described below. Operation Condition Fade in When either of the following conditions is met, the center console spot light fades in. The power switch is on (ACC). The power switch is on (IG). Fade out The power switch is off.

DESCRIPTION

This circuit detects the power switch on (IG) or off condition, and sends it to the main body ECU (multiplex network body ECU).

Scheme 1

This circuit detects the power switch on (ACC) or off condition, and sends it to the main body ECU (multiplex network body ECU).

Scheme 2

The main body ECU (multiplex network body ECU) detects the condition of each door courtesy light switch.

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Main Body / Data List. Read the display on the Techstream. MAIN BODY Tester Display Measurement Item/Range Normal Condition Diagnostic Note RR Door Courtesy SW Rear door courtesy light switch RH signal/ON or OFF ON: Rear door RH open OFF: Rear door RH closed - RL Door Courtesy SW Rear door courtesy light switch LH signal/ON or OFF ON: Rear door LH open OFF: Rear door LH closed - Back Door Courtesy SW Back door courtesy light switch signal/ON or OFF ON: Back door open OFF: Back door closed - FR Door Courtesy Front door RH condition signal/ON or OFF ON: Front door RH closed OFF: Front door RH open - FL Door Courtesy Front door LH condition signal/ON or OFF ON: Front door LH closed OFF: Front door LH open - OK Normal conditions listed above are displayed. Result Result Proceed to OK A Front door courtesy light switch LH or RH does not operate B Rear door courtesy light switch LH or RH does not operate C Back door courtesy light switch does not operate D B --> See step 2 C --> See step 5 D --> See step 7 A --> See step 10
2. INSPECT FRONT DOOR COURTESY LIGHT SWITCH ASSEMBLY (LH OR RH) Disconnect the front door courtesy light switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 1 - Body ground Pushed 10 kohms or higher 1 - Body ground Not pushed Below 1 ohms TEXT IN ILLUSTRATION *a Component without harness connected (Front Door Courtesy Light Switch Assembly) NG --> See step 9 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - SWITCH) for Front LH Disconnect the 2D instrument panel junction block assembly connector. Disconnect the P5 front door courtesy light switch assembly LH connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition P5-1 - 2D-35 Always Below 1 ohms P5-1 - Body ground Always 10 kohms or higher for Front RH Disconnect the 2D instrument panel junction block assembly connector. Disconnect the Q3 front door courtesy light switch assembly RH connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Q3-1 - 2D-36 Always Below 1 ohms Q3-1 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY for Front LH Remove the instrument panel junction block assembly. Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information) . Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly. Measure the resistance according to the value(s) in the table below. TEXT IN ILLUSTRATION *a Component without harness connected (Instrument Panel Junction Block Assembly) *b Component without harness connected (Instrument Panel Junction Block Assembly) Standard Resistance Tester Connection Condition Specified Condition 2D-35 - A-2 (FLCY) Always Below 1 ohms 2D-35 - Body ground Always 10 kohms or higher for Front RH Remove the instrument panel junction block assembly. Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information) . Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly. Measure the resistance according to the value(s) in the table below. TEXT IN ILLUSTRATION *a Component without harness connected (Instrument Panel Junction Block Assembly) *b Component without harness connected (Instrument Panel Junction Block Assembly) Standard Resistance Tester Connection Condition Specified Condition 2D-36 - A-4 (FRCY) Always Below 1 ohms 2D-36 - Body ground Always 10 kohms or higher NG --> See step 14 OK --> See step 11
5. INSPECT REAR DOOR COURTESY LIGHT SWITCH ASSEMBLY (LH OR RH) Disconnect the rear door courtesy light switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 1 - Body ground Pushed 10 kohms or higher 1 - Body ground Not pushed Below 1 ohms TEXT IN ILLUSTRATION *a Component without harness connected (Rear Door Courtesy Light Switch Assembly) NG --> See step 12 OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - REAR COURTESY LIGHT SWITCH) for Rear LH Disconnect the H18 main body ECU (multiplex network body ECU) connector. Disconnect the P12 rear door courtesy light switch assembly LH connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition P12-1 - H18-3 (LCTY) Always Below 1 ohms P12-1 - Body ground Always 10 kohms or higher for Rear RH Disconnect the H16 main body ECU (multiplex network body ECU) connector. Disconnect the Q7 rear door courtesy light switch assembly RH connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Q7-1 - H16-6 (RCTY) Always Below 1 ohms Q7-1 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 11
7. INSPECT BACK DOOR LOCK ASSEMBLY Remove the back door lock assembly. Refer to «REMOVAL»(ref-568815-S42488257262013072300000) . Check the operation of the door lock motor. Move the door lock to the lock position. Apply auxiliary battery voltage to the door lock motor and check the operation of the door lock motor. OK Connection Result Auxiliary battery positive (+) --> Terminal 4 (ACT+) Auxiliary battery negative (-) --> Terminal 3 (ACT-) Unlocks Check the operation of the door courtesy switch. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 1 (E) - 2 (+) Locked 10 kohms or higher 1 (E) - 2 (+) Unlocked Below 1 ohms TEXT IN ILLUSTRATION *a Component without harness connected (Back Door Lock Assembly) *b Lock *c Unlock NG --> See step 13 OK: Go to next step
8. CHECK HARNESS AND CONNECTOR (BACK DOOR LOCK - MAIN BODY ECU) Disconnect the H16 main body ECU (multiplex network body ECU) connector. Disconnect the Q17 back door lock assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Q17-2 (+) - H16-19 (BCTY) Always Below 1 ohms Q17-2 (+) - Body ground Always 10 kohms or higher Q17-1 (E) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 11
9. REPLACE FRONT DOOR COURTESY LIGHT SWITCH ASSEMBLY. Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/interiorillumination-lights/#lighting-system-interior-service-information)
10. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568600-S37783609732013072300000)
11. REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information)
12. REPLACE REAR DOOR COURTESY LIGHT SWITCH ASSEMBLY. Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/interiorillumination-lights/#lighting-system-interior-service-information)
13. REPLACE BACK DOOR LOCK ASSEMBLY. Refer to «REMOVAL»(ref-568815-S42488257262013072300000)
14. REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information)

The main body ECU (multiplex network body ECU) controls the front interior lights and rear interior light.

Scheme 8

The main body ECU (multiplex network ECU) controls the footwell lights.

Scheme 9

The main body ECU (multiplex network body ECU) controls the center console spot light.

Scheme 10

The illuminated entry system controls the power switch illumination.

Scheme 11

Scheme 12

1. PERFORM ACTIVE TEST USING TECHSTREAM Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Smart Access / Active Test. Check that the illumination operates. SMART ACCESS Tester Display Test Part Control Range Diagnostic Note Power/Engine SW Light Power switch illumination ON/OFF All doors closed OK Power switch illumination comes on. NG --> See step 2 OK --> See step 5
2. INSPECT POWER SWITCH Remove the power switch. Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/starter/#power-switch-starting-system-service-information) . Connect a positive (+) lead from the auxiliary battery to terminal 11 (SWIL) and a negative (-) lead to terminal 5 (GND). Check that the power switch illumination comes on. OK Power switch illumination comes on. TEXT IN ILLUSTRATION *a Component without harness connected (Power Switch) NG --> See step 4 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (POWER SWITCH - CERTIFICATION ECU AND BODY GROUND) Disconnect the H1 certification ECU (smart key ECU assembly) connector. Disconnect the H78 power switch connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition H78-11 (SWIL) - H1-11 (SWIL) Always Below 1 ohms H78-11 (SWIL) - Body ground Always 10 kohms or higher H78-5 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 6
4. REPLACE POWER SWITCH. Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/starter/#power-switch-starting-system-service-information)
5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568600-S37783609732013072300000)
6. REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to «REMOVAL»(ref-568797-S38879700432013072300000)

The main body ECU (multiplex network body ECU) detects the condition of each door unlock detection switch.

Scheme 13

Scheme 14

1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Main Body / Data List. Read the display on the Techstream. MAIN BODY Tester Display Measurement Item/Range Normal Condition Diagnostic Note FL Door Lock Pos Front door unlock detection switch LH signal/ON or OFF ON: Front door LH unlocked OFF: Front door LH locked - FR Door Lock Pos Front door unlock detection switch RH signal/ON or OFF ON: Front door RH unlocked OFF: Front door RH locked - RL-Door Lock Pos SW Rear door unlock detection switch LH signal/ON or OFF ON: Rear door LH unlocked OFF: Rear door LH locked - RR-Door Lock Pos SW Rear door unlock detection switch RH signal/ON or OFF ON: Rear door RH unlocked OFF: Rear door RH locked - Result Result Proceed to OK A Front door unlock detection switch LH does not operate B Front door unlock detection switch RH does not operate C Rear door unlock detection switch LH does not operate D Rear door unlock detection switch RH does not operate E B --> See step 2 C --> See step 4 D --> See step 6 E --> See step 9 A --> See step 11
2. INSPECT FRONT DOOR LOCK ASSEMBLY LH Inspect the front door lock assembly LH. Refer to «INSPECTION»(ref-568815-S20114675082013072300000) . OK Front door lock assembly LH is normal. NG --> See step 12 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (FRONT DOOR LOCK ASSEMBLY LH - MAIN BODY ECU AND BODY GROUND) Disconnect the K3 front door lock assembly LH connector. Disconnect the H16 main body ECU (multiplex network body ECU) connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition K3-8 (LSSR) - H16-7 (LSFL) Always Below 1 ohms K3-8 (LSSR) - Body ground Always 10 kohms or higher K3-7 (E) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 16
4. INSPECT FRONT DOOR LOCK ASSEMBLY RH Inspect the front door lock assembly RH. Refer to «INSPECTION»(ref-568815-S20114675082013072300000) . OK Front door lock assembly RH is normal. NG --> See step 13 OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (FRONT DOOR LOCK ASSEMBLY RH - MAIN BODY ECU AND BODY GROUND) Disconnect the J3 front door lock assembly RH connector. Disconnect the H16 main body ECU (multiplex network body ECU) connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J3-7 (LSSR) - H16-18 (LSFR) Always Below 1 ohms J3-7 (LSSR) - Body ground Always 10 kohms or higher J3-8 (E) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 16
6. INSPECT REAR DOOR LOCK ASSEMBLY LH Inspect the rear door lock assembly LH. Refer to «INSPECTION»(ref-568815-S19570587952013072300000) . OK Rear door lock assembly LH is normal. NG --> See step 14 OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (REAR DOOR LOCK ASSEMBLY LH - JUNCTION BLOCK AND BODY GROUND) Disconnect the M1 rear door lock assembly LH connector. Disconnect the 2D instrument panel junction block assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition M1-6 (LSSR) - 2D-25 Always Below 1 ohms M1-6 (LSSR) - Body ground Always 10 kohms or higher M1-9 (E) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Remove the instrument panel junction block assembly. Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information) . Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly. Measure the resistance according to the value(s) in the table below. TEXT IN ILLUSTRATION *a Component without harness connected (Instrument Panel Junction Block Assembly) *b Component without harness connected (Instrument Panel Junction Block Assembly) Standard Resistance Tester Connection Condition Specified Condition 2D-25 - A-5 (LSWL) Always Below 1 ohms 2D-25 - Body ground Always 10 kohms or higher NG --> See step 17 OK --> See step 16
9. INSPECT REAR DOOR LOCK ASSEMBLY RH Inspect the rear door lock assembly RH. Refer to «INSPECTION»(ref-568815-S19570587952013072300000) . OK Rear door lock assembly RH is normal. NG --> See step 15 OK: Go to next step
10. CHECK HARNESS AND CONNECTOR (REAR DOOR LOCK ASSEMBLY RH - MAIN BODY ECU AND BODY GROUND) Disconnect the L1 rear door lock assembly RH connector. Disconnect the H17 main body ECU (multiplex network body ECU) connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition L1-6 (LSSR) - H17-2 (LSWR) Always Below 1 ohms L1-6 (LSSR) - Body ground Always 10 kohms or higher L1-9 (E) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 16
11. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568600-S37783609732013072300000)
12. REPLACE FRONT DOOR LOCK ASSEMBLY LH. Refer to «REMOVAL»(ref-568815-S23038570332013072300000)
13. REPLACE FRONT DOOR LOCK ASSEMBLY RH. Refer to «REMOVAL»(ref-568815-S23038570332013072300000)
14. REPLACE REAR DOOR LOCK ASSEMBLY LH. Refer to «REMOVAL»(ref-568815-S06700484572013072300000)
15. REPLACE REAR DOOR LOCK ASSEMBLY RH. Refer to «REMOVAL»(ref-568815-S06700484572013072300000)
16. REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information)
17. REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information)

See also:
• INSPECTION
• REMOVAL
• REMOVAL