Lexus ES: Open in B Power Line (B242F)
DESCRIPTION
The headlight ECU sub-assembly operates using the power source voltage input from the IG terminal and ECUB terminal.
The power source voltage of the ECUB terminal is supplied when the main body ECU (multiplex network body ECU) turns the ECUB power supply relay (H-LP LH relay and H-LP RH relay) to ON.
The headlight ECU sub-assembly compares the power source voltage supply condition of the IG terminal and ECUB terminal and monitors the result.
for LED Type Turn Signal Light| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | DTC Output from |
|---|---|---|---|---|
| B242F | Open in B Power Line |
|
| AFS |
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | DTC Output from |
|---|---|---|---|---|
| B242F | Open in B Power Line |
|
| AFS (Sub) |
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | DTC Output from |
|---|---|---|---|---|
| B242F | Open in B Power Line |
|
| HL AutoLeveling |
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | DTC Output from |
|---|---|---|---|---|
| B242F | Open in B Power Line |
|
| HL AutoLeveling (Sub) |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following procedure.
-
Before replacing the main body ECU (multiplex network body ECU), refer to Registration.
Click here
.gif)
-
If the headlight ECU sub-assembly LH has been replaced, it is necessary to synchronize the vehicle information and initialize the headlight ECU sub-assembly LH.*1
Click here
-
If the headlight ECU sub-assembly LH has been replaced, it is necessary to synchronize the vehicle information the headlight ECU sub-assembly LH.*2
Click here
-
When replacing the headlight ECU sub-assembly LH, always replace it with a new one. If a headlight ECU sub-assembly LH which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.
- *1: for LED Type Turn Signal Light
- *2: for Bulb Type Turn Signal Light
PROCEDURE
| 1. | CONFIRM MODEL |
(a) Choose the model to be inspected.
| Result | Proceed to |
|---|---|
| for LED Type Turn Signal Light | A |
| for Bulb Type Turn Signal Light | B |
| B | .gif) | GO TO STEP 4 |
|
.gif)
| 2. | CLEAR DTC |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / AFS or AFS (Sub) / Trouble Codes.
(e) Clear the DTCs.
Body Electrical > AFS > Clear DTCs Body Electrical > AFS (Sub) > Clear DTCs
|
| 3. | CHECK FOR DTC |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Wait 10 seconds or more.
(d) Turn the Techstream on.
(e) Enter the following menus: Body Electrical / AFS or AFS (Sub) / Trouble Codes.
(f) Check for DTCs.
Body Electrical > AFS > Trouble Codes Body Electrical > AFS (Sub) > Trouble CodesOK:
DTC B242F is not output.
| Result | Proceed to |
|---|---|
| OK | A |
| NG (DTC output from headlight ECU sub-assembly LH) | B |
| NG (DTC output from headlight ECU sub-assembly RH) | C |
| A | | USE SIMULATION METHOD TO CHECK |
| B | | GO TO STEP 6 |
| C | | GO TO STEP 13 |
| 4. | CLEAR DTC |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / HL AutoLeveling or HL AutoLeveling (Sub) / Trouble Codes.
(e) Clear the DTCs.
Body Electrical > HL AutoLeveling > Clear DTCs Body Electrical > HL AutoLeveling (Sub) > Clear DTCs
|
| 5. | CHECK FOR DTC |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Wait 10 seconds or more.
(d) Turn the Techstream on.
(e) Enter the following menus: Body Electrical / HL AutoLeveling or HL AutoLeveling (Sub) / Trouble Codes.
(f) Check for DTCs.
Body Electrical > HL AutoLeveling > Trouble Codes Body Electrical > HL AutoLeveling (Sub) > Trouble CodesOK:
DTC B242F is not output.
| Result | Proceed to |
|---|---|
| OK | A |
| NG (DTC output from headlight ECU sub-assembly LH) | B |
| NG (DTC output from headlight ECU sub-assembly RH) | C |
| A | | USE SIMULATION METHOD TO CHECK |
| C | | GO TO STEP 13 |
|
| 6. | INSPECT HEADLIGHT ECU SUB-ASSEMBLY LH (ECUB TERMINAL VOLTAGE) |
| *a | Front view of wire harness connector (to Headlight ECU Sub-assembly LH) |
(a) Disconnect the A78 headlight ECU sub-assembly LH connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A78-13 (ECUB) - Body ground | Power switch on (IG) | 9.5 to 14 V |
| NG | | GO TO STEP 8 |
|
| 7. | CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH - BODY GROUND) |
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A78-12 (GND) - Body ground | Always | Below 1 Ω |
| OK | | REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
| 8. | INSPECT H-LP LH RELAY |
(a) Inspect the H-LP LH relay.
Click here
| NG | | REPLACE H-LP LH RELAY |
|
| 9. | CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - HEADLIGHT ECU SUB-ASSEMBLY LH) |
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 3 (H-LP LH relay) - A78-13 (ECUB) | Always | Below 1 Ω |
| 3 (H-LP LH relay) or A78-13 (ECUB) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 10. | CHECK HARNESS AND CONNECTOR (POWER SOURCE - H-LP LH RELAY) |
(a) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 2 (H-LP LH relay) - Body ground | Power switch off | 11 to 14 V |
| 5 (H-LP LH relay) - Body ground | Power switch off | 11 to 14 V |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 11. | CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) |
(a) Disconnect the 3F instrument panel junction block assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 1 (H-LP LH relay) - 3F-31 | Always | Below 1 Ω |
| 1 (H-LP LH relay) or 3F-31 - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 12. | INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
.png)
| *a | Component without harness connected (Instrument Panel Junction Block Assembly) | - | - |
(a) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
Click here
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 3F-31 - MB-15 (HRLY) | Always | Below 1 Ω |
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | | REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
| 13. | INSPECT HEADLIGHT ECU SUB-ASSEMBLY RH (ECUB TERMINAL VOLTAGE) |
| *a | Front view of wire harness connector (to Headlight ECU Sub-assembly RH) |
(a) Disconnect the A79 headlight ECU sub-assembly RH connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A79-13 (ECUB) - Body ground | Power switch on (IG) | 9.5 to 14 V |
| NG | | GO TO STEP 15 |
|
| 14. | CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY RH - BODY GROUND) |
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A79-12 (GND) - Body ground | Always | Below 1 Ω |
| OK | | REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
| 15. | INSPECT H-LP RH RELAY |
(a) Inspect the H-LP RH relay.
Click here
| NG | | REPLACE H-LP RH RELAY |
|
| 16. | CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - HEADLIGHT ECU SUB-ASSEMBLY RH) |
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 5 (H-LP RH relay) - A79-13 (ECUB) | Always | Below 1 Ω |
| 5 (H-LP RH relay) or A79-13 (ECUB) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 17. | CHECK HARNESS AND CONNECTOR (POWER SOURCE - H-LP RH RELAY) |
(a) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 1 (H-LP RH relay) - Body ground | Power switch off | 11 to 14 V |
| 3 (H-LP RH relay) - Body ground | Power switch off | 11 to 14 V |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 18. | CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) |
(a) Disconnect the G37 main body ECU (multiplex network body ECU) connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 2 (H-LP RH relay) - G37-12 (HRY2) | Always | Below 1 Ω |
| 2 (H-LP RH relay) or G37-12 (HRY2) - Body ground | Always | 10 kΩ or higher |
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
READ NEXT:
Headlight LH Circuit (B2439,B243A)
DESCRIPTION The headlight ECU sub-assembly LH and headlight ECU sub-assembly RH internally boost the power supply voltage to ensure a constant supplied current for the lo/hi beam LED of their respecti
Left Low Beam Fan Malfunction (B243D,B243E)
DESCRIPTION The headlight ECU sub-assembly operates the low beam fan to cool the headlight LED unit in order to prevent the headlight LED unit from overheating. Illuminates the low beam headlights and
Height Sensor Initialization Incomplete (B2450)
DESCRIPTION The headlight ECU sub-assembly LH stores this DTC if initialization has not been performed after it was replaced. DTC No. Detection Item DTC Detection Condition Trouble Area DTC
SEE MORE:
Problem Symptoms Table
PROBLEM SYMPTOMS TABLE HINT:
Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspect
Adjustment
ADJUSTMENT CAUTION / NOTICE / HINT The necessary procedures (adjustment, calibration, initialization or registration) that must be performed after parts are removed and installed, or replaced during park/neutral position switch assembly removal/installation are shown below. Necessary Procedures Afte
