Toyota CH-R Service Manual: Headlight ECU Communication Stop Mode

DESCRIPTION

Detection Item	Symptom	Trouble Area
Headlight ECU Communication Stop Mode	Any of the following conditions are met: Communication stop for "Headlight swivel (AFS)" is indicated on the "Communication Bus Check" screen of the Techstream. Click here Communication stop history for "Headlight swivel (AFS)" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "Headlight swivel (AFS)" is 6 or more.) Click here Communication system DTCs (DTCs that start with U) that correspond to "AFS ECU Communication Stop Mode" in "DTC Combination Table" are output. Click here	Headlight ECU sub-assembly LH branch line or connector Power source circuit of Headlight ECU sub-assembly LH Headlight ECU sub-assembly LH ground circuit Headlight ECU sub-assembly LH

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
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Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
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After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the ignition switch to ON and wait at least approximately 20 seconds.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.
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Inspect the fuses for circuits related to this system before performing the following procedure.

HINT:

Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

1.	CHECK FOR OPEN IN CAN BUS LINES (HEADLIGHT ECU SUB-ASSEMBLY LH BRANCH LINE)

(a) Disconnect the cable from the negative (-) battery terminal.

*a	Front view of wire harness connector (to Headlight ECU Sub-assembly LH)

(b) Disconnect the headlight ECU sub-assembly LH connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A16-24 (CANH) - A16-23 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY LH)

2.	CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

(a) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A16-12 (GND) - Body ground	Always	Below 1 Ω

(b) Reconnect the cable to the negative (-) battery terminal.

*a	Front view of wire harness connector (to Headlight ECU Sub-assembly LH)

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A16-4 (IG) - Body ground	Ignition switch ON	11 to 14 V
A16-13 (ECUB) - Body ground	Ignition switch ON	11 to 14 V

REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

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