Toyota Yaris: Can Communication System / 4WD Control ECU Communication Stop Mode

Toyota Yaris XP210 (2020-2026) Reapir and Service Manual / Power Source & Network / Networking / Can Communication System / 4WD Control ECU Communication Stop Mode

DESCRIPTION

Detection Item	Symptom	Trouble Area
4WD Control ECU Communication Stop Mode	Communication stop for "Four Wheel Drive Control" is indicated on the "Communication Bus Check" screen of the GTS. Click here	4WD ECU assembly branch line or connector Power source circuit of 4WD ECU assembly 4WD ECU assembly ground circuit 4WD ECU assembly

Detection Item

Symptom

Trouble Area

4WD Control ECU Communication Stop Mode

Communication stop for "Four Wheel Drive Control" is indicated on the "Communication Bus Check" screen of the GTS.

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4WD ECU assembly branch line or connector
Power source circuit of 4WD ECU assembly
4WD ECU assembly ground circuit
4WD ECU assembly

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

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 (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.
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When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.
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Some parts must be initialized and set when replacing or removing and installing parts.
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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 for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
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 (4WD ECU ASSEMBLY BRANCH LINE)

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

(b) Disconnect the 4WD ECU assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
O120-17 (CANH) - O120-26 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

*a	Front view of wire harness connector (to 4WD ECU Assembly)

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (4WD ECU ASSEMBLY)

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
O119-1 (GND) - Body ground	Cable disconnected from negative (-) battery terminal	Below 1 Ω

*a	Front view of wire harness connector (to 4WD ECU Assembly)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
O119-2 (BSLC) - Body ground	Always	11 to 14 V
O119-24 (IG1) - Body ground	Ignition switch ON	11 to 14 V

REPLACE 4WD ECU ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

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Other information:

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