Headlight ECU LH Communication Stop Mode [03/2023 - ]: Procedure
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- CHECK FOR OPEN IN CAN BUS LINES (HEADLIGHT ECU SUB-ASSEMBLY LH BRANCH LINE)
- Disconnect the cable from the negative (-) battery terminal.
- Disconnect the A49 headlight ECU sub-assembly LH connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A49-24 (CANH) - A49-23 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Result
Result OK NG
Result:
NG
REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH)
Result:
OK
See step 2
- CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A49-12 (GND) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω - Reconnect the cable to the negative (-) battery terminal.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition A49-6 (IGR) - Body ground Ignition switch ON 11 to 14 V Result
Result OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
Result:
OK
See step 3
- Measure the resistance according to the value(s) in the table below.
- CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition A49-13 (ECUB) - Body ground Ignition switch ON 9.5 to 14 V Result
Result OK NG
Result:
OK
REPLACE HEADLIGTH ECU SUB-ASSEMBLY LH. Refer to REMOVAL [11/2021 - ]
Result:
NG
See step 4
- Measure the voltage according to the value(s) in the table below.
- CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH - SEMICONDUCTOR POWER INTEGRATION ECU)
- Disconnect the cable from the negative (-) battery terminal.
- Disconnect the A77 semiconductor power integration ECU connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A77-1 (L) - A49-13 (ECUB) Cable disconnected from negative (-) battery terminal Below 1 Ω Result
Result OK NG
Result:
OK
REPLACE SEMICONDUCTOR POWER INTEGRATION ECU. Refer to REMOVAL [11/2021 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR