Lighting System (Diagnostic Codes & Circuit Tests): Overview Lexus CT I

DESCRIPTION

The automatic light control sensor detects ambient light, converts it into an electrical signal, and outputs it to the main body ECU (multiplex network body ECU). The main body ECU (multiplex network body ECU) turns on or off the headlights and taillights according to the signal.

Scheme 159

Scheme 160

Scheme 161

Scheme 162

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 Illumination Rate info Illumination rate information/0 ms to 2162.65 ms Value is output according to ambient light levels - OK Normal condition listed above is displayed. NG --> See step 2 OK --> See step 5
2. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - AUTOMATIC LIGHT CONTROL SENSOR) Disconnect the I1 automatic light control sensor 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 H16-22 (CLTE) - I1-3 (CLTE) Always Below 1 ohms H16-21 (CLTS) - I1-5 (CLTS) Always Below 1 ohms H16-20 (CLTB) - I1-6 (CLTB) Always Below 1 ohms H16-22 (CLTE) - Body ground Always 10 kohms or higher H16-21 (CLTS) - Body ground Always 10 kohms or higher H16-20 (CLTB) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. INSPECT MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Reconnect the H16 main body ECU (multiplex network body ECU) connector. Measure the voltage and resistance according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition H16-20 (CLTB) - H16-22 (CLTE) Power switch off Below 1 V Power switch on (IG) 11 to 14 V Standard Resistance Tester Connection Condition Specified Condition H16-22 (CLTE) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *a Component with harness connected (Main Body ECU (Multiplex Network Body ECU)) NG --> See step 5 OK: Go to next step
4. INSPECT AUTOMATIC LIGHT CONTROL SENSOR Reconnect the I1 automatic light control sensor connector. Connect an oscilloscope to the automatic light control sensor connector. TEXT IN ILLUSTRATION *a Component with harness connected (Automatic Light Control Sensor) Check the waveform. OK Tester Connection Tool Setting Condition Specified Condition I1-3 (CLTE) - I1-5 (CLTS) 5 V/DIV., 5 ms./DIV. Power switch on (IG), light control switch in AUTO position Correct waveform is as shown HINT: If the ambient light becomes brighter, width A becomes narrower. NG --> See step 6 OK --> See step 5
5. REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information)
6. REPLACE AUTOMATIC LIGHT CONTROL SENSOR. Refer to «REMOVAL»(ref-568776-S07746920522013072300000)

The DTC is stored when the headlight leveling ECU assembly detects malfunctions in the rear height control sensor sub-assembly power source or rear height control sensor sub-assembly.

Scheme 163

The headlight leveling ECU assembly receives signals indicating the height of the vehicle from the rear height control sensor sub-assembly.

When the headlight leveling ECU assembly detects a malfunction in itself, the DTC is stored.

These DTCs are stored when the low beam headlights do not illuminate, or a malfunction is detected in the communication between the headlight assembly and main body ECU (multiplex network body ECU).

Note. DTC B2430 and B2431 are not stored until 12 seconds have elapsed after turning the power switch on (READY).

Scheme 164

The headlight leveling ECU assembly stores this DTC if initialization has not been performed after the ECU was replaced.

The headlight leveling ECU sets this DTC if the vehicle specifications have not been stored in the leveling ECU.

HINT

The vehicle specifications are stored in the ECU at the factory.

The headlight leveling ECU assembly stores this DTC if the sensor value received from the height control sensor is out of range when performing initialization of the headlight leveling ECU assembly; for example, the vehicle is not level or being jacked up.

This DTC is stored if the headlight leveling ECU assembly is not installed properly.

The main body ECU (multiplex network body ECU) receives the following switch information

1. Light control switch position is off, tail, head or AUTO
2. Dimmer switch position is high, low or high flash (pass)
3. Front fog light switch position is on or off

Scheme 165

Scheme 166

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 Dimmer SW Dimmer switch high position signal/ON or OFF ON: Dimmer switch in high or high flash position OFF: Dimmer switch in low position - Passing Light SW Dimmer switch high flash position (pass) signal/ON or OFF ON: Dimmer switch in high flash position OFF: Dimmer switch not in high flash position - Front Fog Light SW Front fog light switch signal/ON or OFF ON: Front fog light switch on OFF: Front fog light switch off - Auto Light SW Light control switch AUTO position signal/ON or OFF ON: Light control switch in AUTO position OFF: Light control switch not in AUTO position - Head Light SW (Head) Light control switch head position signal/ON or OFF ON: Light control switch in head position OFF: Light control switch not in head position - Head Light SW (Tail) Light control switch tail position signal/ON or OFF ON: Light control switch in tail or head position OFF: Light control switch in neither tail nor head position - OK Normal conditions listed above are displayed. NG --> See step 2 OK --> See step 4
2. INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY HINT: Inspect the items that did not change as a result of monitoring the Data List. Remove the headlight dimmer switch assembly. Refer to «REMOVAL»(ref-568776-S36005825872013072300000) . Measure the resistance according to the value(s) in the table below. Standard Resistance LIGHT CONTROL SWITCH (W/ DRL OFF FUNCTION) Tester Connection Switch Condition Specified Condition 18 (T) - 12 (EL) Light control switch off (DRL OFF position) 10 kohms or higher 20 (H) - 12 (EL) Light control switch off (DRL OFF position) 10 kohms or higher 19 (A) - 12 (EL) Light control switch off (DRL OFF position) 10 kohms or higher 19 (A) - 12 (EL) Light control switch in AUTO position Below 1 ohms 18 (T) - 12 (EL) Light control switch in tail position Below 1 ohms 18 (T) - 12 (EL) Light control switch in head position Below 1 ohms 20 (H) - 12 (EL) Light control switch in head position Below 1 ohms LIGHT CONTROL SWITCH (W/O DRL OFF FUNCTION) Tester Connection Switch Condition Specified Condition 18 (T) - 12 (EL) Light control switch off 10 kohms or higher 20 (H) - 12 (EL) Light control switch off 10 kohms or higher 19 (A) - 12 (EL) Light control switch off 10 kohms or higher 18 (T) - 12 (EL) Light control switch in tail position Below 1 ohms 18 (T) - 12 (EL) Light control switch in head position Below 1 ohms 20 (H) - 12 (EL) Light control switch in head position Below 1 ohms 19 (A) - 12 (EL) Light control switch in AUTO position Below 1 ohms DIMMER SWITCH Tester Connection Switch Condition Specified Condition 11 (HU) - 12 (EL) Dimmer switch in low position 10 kohms or higher 11 (HU) - 12 (EL) Dimmer switch in high position Below 1 ohms 12 (EL) - 17 (HF) Dimmer switch in high flash position Below 1 ohms FRONT FOG LIGHT SWITCH Tester Connection Switch Condition Specified Condition 3 (LFG) - 4 (BFG) Fog light switch off 10 kohms or higher 3 (LFG) - 4 (BFG) Fog light switch on Below 1 ohms OK Headlight dimmer switch assembly is normal. TEXT IN ILLUSTRATION *a Component without harness connected (Headlight Dimmer Switch Assembly) NG --> See step 5 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - HEADLIGHT DIMMER SWITCH ASSEMBLY) Disconnect the H26 headlight dimmer switch assembly 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 H26-4 (BFG) - H16-27 (FFOG) Always Below 1 ohms H26-11 (HU) - H16-5 (HU) Always Below 1 ohms H26-17 (HF) - H16-8 (HF) Always Below 1 ohms H26-18 (T) - H16-30 (TAIL) Always Below 1 ohms H26-19 (A) - H16-28 (A) Always Below 1 ohms H26-20 (H) - H16-29 (HEAD) Always Below 1 ohms H26-4 (BFG) - Body ground Always 10 kohms or higher H26-11 (HU) - Body ground Always 10 kohms or higher H26-17 (HF) - Body ground Always 10 kohms or higher H26-18 (T) - Body ground Always 10 kohms or higher H26-19 (A) - Body ground Always 10 kohms or higher H26-20 (H) - Body ground Always 10 kohms or higher H26-12 (EL) - Body ground Always Below 1 ohms H26-3 (LFG) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 6
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568605-S19186653942013072300000)
5. REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY. Refer to «REMOVAL»(ref-568776-S36005825872013072300000)
6. REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). 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 daytime running lights.

The system illuminates the high-intensity LED parking lights (high-intensity circuit).

Scheme 167

The main body ECU (multiplex network body ECU) controls the front fog light relay.

Scheme 168

The main body ECU (multiplex network body ECU) receives the hazard switch ON signal and controls the operation of the turn signal flasher assembly.

Scheme 169

Scheme 170

Scheme 171

Scheme 172

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 Hazard Switch Hazard switch signal/ON or OFF ON: Hazard switch on OFF: Hazard switch off - OK Normal conditions listed above are displayed. NG --> See step 3 OK: Go to next step
2. 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 / Main Body / Active Test. Check that the hazard lights illuminate. MAIN BODY Tester Display Test Part Control Range Diagnostic Note Hazard Hazard warning lights ON/OFF - OK Hazard lights illuminate. NG --> See step 5 OK --> See step 11
3. INSPECT HAZARD WARNING SIGNAL SWITCH ASSEMBLY Remove the hazard warning signal switch assembly. Refer to «REMOVAL»(ref-568776-S36181790502013072300000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 6 (HAZ) - 3 (GND) Hazard switch on Below 1 ohms 6 (HAZ) - 3 (GND) Hazard switch off 10 kohms or higher TEXT IN ILLUSTRATION *a Component without harness connected (Hazard Warning Signal Switch Assembly) NG --> See step 12 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (HAZARD WARNING SIGNAL SWITCH - MAIN BODY ECU) 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 H82-6 (HAZ) - H17-17 (HZSW) Always Below 1 ohms H82-6 (HAZ) - Body ground Always 10 kohms or higher H82-3 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 10
5. CHECK HARNESS AND CONNECTOR (TURN & HAZ FUSE - TURN SIGNAL FLASHER ASSEMBLY) Disconnect the H35 turn signal flasher assembly connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition H35-4 (B) - Body ground Always 11 to 14 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition H35-7 (E) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
6. INSPECT TURN SIGNAL FLASHER ASSEMBLY Reconnect the H35 turn signal flasher assembly connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition H35-8 (HAZ) - Body ground Hazard switch off 9 V or higher H35-8 (HAZ) - Body ground Hazard switch on Below 1 V TEXT IN ILLUSTRATION *a Component without harness connected (Turn Signal Flasher Assembly) Result Result Proceed to NG (when the hazard switch on) A NG (when the hazard switch off) B OK B B --> See step 13 A: Go to next step
7. CHECK HARNESS AND CONNECTOR (TURN SIGNAL FLASHER - HAZARD WARNING SIGNAL SWITCH ASSEMBLY) Disconnect the H35 turn signal flasher assembly connector. Disconnect the H82 hazard warning signal switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition H35-8 (HAZ) - H82-4 (FLSW) Always Below 1 ohms H35-8 (HAZ) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. CHECK HARNESS AND CONNECTOR (HAZARD WARNING SIGNAL SWITCH ASSEMBLY - MAIN BODY ECU) 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 H82-5 (LJB) - H16-3 (HAZ) Always Below 1 ohms H82-5 (LJB) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
9. INSPECT HAZARD WARNING SIGNAL SWITCH ASSEMBLY Reconnect the H35 turn signal flasher assembly connector. Reconnect the H82 hazard warning signal switch assembly connector. Reconnect the H16 main body ECU (multiplex network body ECU) connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition H82-5 (LJB) - Body ground Power switch off 11 to 14 V TEXT IN ILLUSTRATION *a Component with harness connected (Hazard Warning Signal Switch Assembly) NG --> See step 12 OK --> See step 10
10. REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information)
11. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568605-S19186653942013072300000)
12. REPLACE HAZARD WARNING SIGNAL SWITCH ASSEMBLY. Refer to «REMOVAL»(ref-568776-S36181790502013072300000)
13. REPLACE TURN SIGNAL FLASHER ASSEMBLY. Refer to «REMOVAL»(ref-568776-S19991943842013072300000)

The power management control ECU controls the back-up lights.

Scheme 173

The headlight leveling ECU assembly detects the status of the low beam headlights.

Scheme 174

The main body ECU (multiplex network body ECU) controls the door mirror foot lights.

Scheme 175

Scheme 176

1. w/o Seat Position Memory
2. w/ Seat Position Memory

Scheme 177

Scheme 178

1. CHECK VEHICLE CONDITION Check the vehicle condition. Result Result Proceed to w/o Seat Position Memory A w/ Seat Position Memory B B --> See step 5 A: Go to next step
2. 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 / Main Body / Active Test. Check that the door mirror foot lights operate. MAIN BODY Tester Display Test Part Control Range Diagnostic Note Side Mirror Foot Light Door mirror foot lights ON/OFF - OK Door mirror foot lights illuminate. NG --> See step 3 OK --> See step 9
3. CHECK OUTER REAR VIEW MIRROR ASSEMBLY Remove the outer rear view mirror assembly that does not illuminate. Refer to «REMOVAL»(ref-568827-S23458436912013072300000) . Connect a positive (+) lead from the auxiliary battery to terminal 2 and a negative (-) lead to terminal 12. Check that the outer mirror foot light comes on. Result Result Proceed to OK A NG (Door mirror foot light LH does not come on) B NG (Door mirror foot light RH does not come on) C TEXT IN ILLUSTRATION *a Component without harness connected (Outer Rear View Mirror Assembly LH) (Outer Rear View Mirror Assembly RH) B --> See step 10 C --> See step 12 A: Go to next step
4. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - OUTER REAR VIEW MIRROR ASSEMBLY) Disconnect the H17 main body ECU (multiplex network body ECU) connector. Disconnect the K6 or J6 outer rear view mirror assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition K6-2 (MLP) - H17-4 (MILE) Always Below 1 ohms J6-2 (MLP) - H17-4 (MILE) Always Below 1 ohms H17-4 (MILE) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 8
5. PERFORM ACTIVE TEST USING TECHSTREAM Connect the Techstream on the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Body Electrical / Mirror L or Mirror R / Active Test. Check that the door mirror foot lights operate. MIRROR L Tester Display Test Part Control Range Diagnostic Note Foot Light Door mirror foot light LH ON/OFF - MIRROR R Tester Display Test Part Control Range Diagnostic Note Foot Light Door mirror foot light RH ON/OFF - Result Result Proceed to OK A NG (Door mirror foot light LH does not come on) B NG (Door mirror foot light RH does not come on) C B --> See step 6 C --> See step 7 A --> See step 9
6. INSPECT OUTER REAR VIEW MIRROR ASSEMBLY LH Remove the outer rear view mirror assembly LH. Refer to «REMOVAL»(ref-568827-S23458436912013072300000) . Connect a positive (+) lead from the auxiliary battery to terminal 2 and a negative (-) lead to terminal 12. Check that the outer mirror foot light comes on. OK Door mirror foot light comes on. TEXT IN ILLUSTRATION *a Component without harness connected (Outer Rear View Mirror Assembly LH) NG --> See step 10 OK --> See step 11
7. INSPECT OUTER REAR VIEW MIRROR ASSEMBLY RH Remove the outer rear view mirror assembly RH. Refer to «REMOVAL»(ref-568827-S23458436912013072300000) . Connect a positive (+) lead from the auxiliary battery to terminal 2 and a negative (-) lead to terminal 12. Check that the outer mirror foot light comes on. OK Door mirror foot light comes on. TEXT IN ILLUSTRATION *a Component without harness connected (Outer Rear View Mirror Assembly RH) NG --> See step 12 OK --> See step 13
8. REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to «REMOVAL»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information)
9. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568605-S19186653942013072300000)
10. REPLACE OUTER REAR VIEW MIRROR ASSEMBLY LH. Refer to «REMOVAL»(ref-568827-S23458436912013072300000)
11. REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY (LH). Refer to «REMOVAL»(ref-568827-S38819182732013072300000)
12. REPLACE OUTER REAR VIEW MIRROR ASSEMBLY RH. Refer to «REMOVAL»(ref-568827-S23458436912013072300000)
13. REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY (RH). Refer to «REMOVAL»(ref-568827-S38819182732013072300000)

The main body ECU (multiplex network body ECU) detects the condition of the parking brake switch assembly.

Scheme 179

Scheme 180

Scheme 181

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 Parking Brake SW Parking brake switch signal/ON or OFF ON: Parking brake switch on OFF: Parking brake switch off - OK Normal conditions listed above are displayed. NG --> See step 2 OK --> See step 5
2. INSPECT PARKING BRAKE SWITCH ASSEMBLY Remove the parking brake switch assembly. Refer to «REMOVAL»(ref-568789-S10488640292013072300000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition Terminal - Nut On (When shaft is not pressed) Below 1 ohms Terminal - Nut Off (When shaft is pressed) 10 kohms or higher TEXT IN ILLUSTRATION *1 Terminal *2 Nut *a Component without harness connected (Parking Brake Switch Assembly) NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (SWITCH - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) Disconnect the 2C 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 A24-1 - 2C-20 Always Below 1 ohms A24-1 - 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 Remove the instrument panel junction block assembly. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 2C-20 - A-12 (PKB) Always Below 1 ohms 2C-20 - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *a Component without harness connected (Instrument Panel Junction Block Assembly) *b Component without harness connected (Instrument Panel Junction Block Assembly) NG --> REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY OK --> See step 7
5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568605-S19186653942013072300000)
6. REPLACE PARKING BRAKE SWITCH ASSEMBLY. Refer to «REMOVAL»(ref-568789-S10488640292013072300000)
7. REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). 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 operation of the TAIL relay.

Scheme 182

Scheme 183

1. for LED Headlight
2. except LED Headlight

This circuit detects the state of the power switch, and sends it to the headlight leveling ECU assembly.

Scheme 184

The headlight leveling ECU assembly actuates the headlight leveling motor according to vehicle conditions.

Scheme 185

The headlight leveling ECU assembly receives the vehicle speed signal from the combination meter assembly.

HINT

1. A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter. The signal is changed to a pulse signal at the transistor in the combination meter. Each ECU controls the respective system based on the pulse signal.
2. If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems in the diagram below will not operate normally.

Scheme 186

1. for 2ZR-FXE

Scheme 187

1. CHECK COMBINATION METER SYSTEM The circuits that send vehicle speed signals to this system are inspected in the meter section. Refer to «Speed Signal Circuit»(ref-568762-S10347095632013072300000) . During inspection for the meter system, if there is an instruction that indicates to go back to inspections for the lighting system, proceed to the next step. NEXT: Go to next step
2. CHECK HARNESS AND CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY - COMBINATION METER ASSEMBLY) Disconnect the H19 combination meter assembly connector. Disconnect the A46 headlight leveling ECU assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A46-16 (SPDR) - H19-40 (+S) Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) Check the output waveform. Remove the combination meter assembly with the connector still connected. Connect an oscilloscope to terminal H19-40 (+S) and body ground. Turn the power switch on (IG). Check the signal waveform according to the condition(s) in the table below. Item Condition Tool setting 5 V/DIV., 20 ms./DIV. Vehicle condition Driving at approx. 20 km/h (12 mph) OK The waveform is displayed as shown in the illustration. TEXT IN ILLUSTRATION *a Component with harness connected (Combination Meter Assembly) HINT: When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows. NG --> See step 5 OK --> See step 4
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568605-S19186653942013072300000)
5. REPLACE COMBINATION METER ASSEMBLY. Refer to «REMOVAL»(ref-568747-S11946107832013072300000)

The headlight beam level control system indicator light in the combination meter assembly comes on for approximately 3 seconds when the power switch is turned on (IG). The indicator light also comes on when the headlight leveling ECU assembly detects a malfunction.

Scheme 188

1. By connecting terminals LVL and CG of the DLC3, the headlight leveling ECU assembly initializes the height control sensor signal.

Scheme 189

The headlight leveling ECU assembly outputs DTC information to the Techstream via this circuit.

Scheme 190

The main body ECU (multiplex network body ECU) controls the headlight relays located within the No. 1 integration relay.

Scheme 191

Scheme 192

1. for LED Headlight
2. except LED Headlight

The main body ECU (multiplex network body ECU) controls the high beam headlights.

Scheme 193

See also:
• REMOVAL