Headlight ECU LH Communication Stop Mode [11/2022 - ]: Procedure
WARNING: This page is about a different car, the 2025 Toyota Corolla Cross, 2024 Toyota Corolla Cross, and 2023 Toyota Corolla Cross. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK FOR OPEN IN CAN BUS LINES (HEADLIGHT ECU SUB-ASSEMBLY LH BRANCH LINE)
- Disconnect the cable from the negative (-) auxiliary battery terminal.
- Disconnect the headlight ECU sub-assembly LH connector.
- Measure the resistance according to the value(s) in the table below.
*a Front view of wire harness connector
(to Headlight ECU Sub-assembly LH)Standard Resistance
Tester Connection Condition Specified Condition A159-24 (CANH) - A159-23 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω Result
Proceed to 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.
*a Front view of wire harness connector
(to Headlight ECU Sub-assembly LH)Standard Resistance
Tester Connection Condition Specified Condition A159-12 (GND) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω - Reconnect the cable to the negative (-) auxiliary battery terminal.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Switch Condition Specified Condition A159-6 (IGR) - Body ground Ignition switch ON 11 to 14 V A159-13 (ECUB) - Body ground Ignition switch ON 11 to 14 V Result
Proceed to OK NG
Result:
OK
REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH
Refer to REMOVAL [09/2021 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
- Measure the resistance according to the value(s) in the table below.