CAN COMMUNICATION SYSTEM Open in CAN Main Bus Line

DESCRIPTION

There may be an open circuit in one of the V Bus main lines and/or a DLC3 branch line when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is 70 Ω or higher.

Symptom	Trouble Area
Resistance between terminals 6 (CANH) and 14 (CANL) of DLC3 is 70 Ω or higher.	DLC3 branch line or connector CAN main bus line or connector ECM Combination meter assembly CAN No. 1 junction connector CAN No. 2 junction connector

This malfunction is not related to the lines of a CAN main bus branch or to ECUs or sensors connected a CAN main bus branch.

WIRING DIAGRAM

INSPECTION PROCEDURE

Note

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, 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 Click here.
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 Click here.
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, turn the blind spot monitor system on using the blind spot monitor main switch (ON/OFF switch), wait at least 31 seconds and then drive the vehicle at a speed of 20 km/h (12 mph) or more for 5 minutes or more. Check that the warning light remains off after turning off following the initial light check.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed Click here.

Tech Tips

Operating the ignition switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.
Connectors that connect to the CAN junction connector can be distinguished by color of their CAN bus lines. When the connectors have been disconnected from the CAN junction connector, reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.

PROCEDURE

CHECK FOR OPEN IN CAN BUS LINES (DLC3 BRANCH LINE)

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

Text in Illustration
*1	DLC3

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

Standard Resistance

Tester Connection	Condition	Specified Condition
I39-6 (CANH) - I39-14 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

Note

When the measured value is 133 Ω or higher and a CAN communication system DTC is output, there may be a fault besides disconnection of the DLC3 branch line. For that reason, troubleshooting should be performed again from How to Proceed with Troubleshooting after repairing the trouble area Click here.

REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3

CHECK FOR OPEN IN CAN BUS LINES (ECM - CAN NO. 2 J/C)

Text in Illustration

*a
Front view of wire harness connector

(to ECM)

Disconnect the ECM connector.

Text in Illustration
*a	Front view of wire harness connector (to ECM)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
A25-13 (CANH) -A25-26 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

Result

Result	Proceed to
OK (for 2GR-FE)	A
OK (for 2AR-FE)	B
NG	C

REPLACE ECM Click here

CHECK FOR OPEN IN CAN BUS LINES (COMBINATION METER ASSEMBLY - CAN NO. 1 J/C) Click here

REPLACE ECM Click here

CHECK FOR OPEN IN CAN BUS LINES (COMBINATION METER ASSEMBLY - CAN NO. 1 J/C)

Reconnect the ECM connector.
Text in Illustration

*a
Front view of wire harness connector

(to Combination Meter Assembly)

Disconnect the combination meter assembly connector.

Text in Illustration
*a	Front view of wire harness connector (to Combination Meter Assembly)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
I18-16 (CANH) - I18-15 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

CHECK FOR OPEN IN CAN BUS LINES (CAN NO. 1 J/C) Click here

REPLACE COMBINATION METER ASSEMBLY Click here

CHECK FOR OPEN IN CAN BUS LINES (CAN NO. 1 J/C)

Reconnect the combination meter assembly connector.

Text in Illustration
*a	Rear view of wire harness connector (to CAN No. 1 Junction Connector)
*b	to Combination Meter Assembly
*c	to CAN No. 2 Junction Connector

Disconnect the CAN No. 1 junction connectors (I94 and I93).

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
I94-1 (CANH) - I94-2 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Combination meter assembly
I93-1 (CANH) - I93-2 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	CAN No. 2 junction connector

Wiring Color

Code	Color (CANH Side)	Color (CANL Side)	Connected to
I94	R	W	Combination meter assembly
I93	B	W	CAN No. 2 junction connector

Note

Before disconnecting the connectors, make a note of where they are connected.
Reconnect each connector to its original position.

Result

Result	Proceed to
OK	A
NG (Combination meter assembly main line)	B
NG (CAN No. 2 junction connector main line)	C

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 1 J/C - COMBINATION METER ASSEMBLY)

CHECK FOR OPEN IN CAN BUS LINES (CAN NO. 2 J/C) Click here

REPLACE CAN NO. 1 JUNCTION CONNECTOR

CHECK FOR OPEN IN CAN BUS LINES (CAN NO. 2 J/C)

Reconnect the CAN No. 1 junction connector (I94 and I93).

Text in Illustration
*a	Rear view of wire harness connector (to CAN No. 2 Junction Connector)
*b	to CAN No. 1 Junction Connector
*c	to ECM

Disconnect the CAN No. 2 junction connectors (I104 and I101).

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
I104-1 (CANH) - I104-2 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	ECM
I101-1 (CANH) - I101-2 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	CAN No. 1 junction connector

Wiring Color

Code	Color (CANH Side)	Color (CANL Side)	Connected to
I104	P	W	ECM
I101	B	W	CAN No. 1 junction connector

Note

Before disconnecting the connectors, make a note of where they are connected.
Reconnect each connector to its original position.

Result

Result	Proceed to
OK	A
NG (CAN No. 1 junction connector main line)	B
NG (ECM main line)	C

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 1 J/C - CAN NO. 2 J/C)

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 2 J/C - ECM)

REPLACE CAN NO. 2 JUNCTION CONNECTOR