CAN COMMUNICATION SYSTEM Check Bus 3 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 6 (CA3H) and 21 (CA3L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom	Trouble Area
Resistance between terminals 6 (CA3H) and 21 (CA3L) of the central gateway ECU (network gateway ECU) is below 54 Ω.	Short in CAN main bus wire Short in CAN branch wire Central gateway ECU (network gateway ECU) Radio receiver assembly Telematics transceiver1 Bus buffer ECU2 Luggage closer motor assembly Rear multiplex network door ECU LH Stereo component equalizer assembly Rear multiplex network door ECU RH No. 7 CAN junction terminal No. 1 CAN junction connector No. 21 CAN junction connector

*1: w/ Telematics Transceiver
*2: w/ Bus Buffer ECU

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

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

Note

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 power 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 turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

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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 power switch on (IG) 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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The following malfunctions may occur if a radio receiver assembly from another vehicle is installed to this vehicle. Therefore, when replacing the radio receiver assembly, be sure to replace it with new one.

Communication malfunction DTC is output
Does not operate normally

Tech Tips

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

CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 CAN JUNCTION CONNECTOR)

Disconnect the cable from the negative (-) auxiliary battery terminal.
Disconnect the G119 No. 1 CAN junction connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
G119-12 (CANH) - G119-1 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Radio receiver assembly
G119-13 (CANH) - G119-2 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	Central gateway ECU (network gateway ECU)
G119-14 (CANH) - G119-3 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	No. 21 CAN junction connector
G119-15 (CANH) - G119-4 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Bus Buffer ECU*1
G119-16 (CANH) - G119-5 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Telematics transceiver*2

*1: w/ Bus Buffer ECU
*2: w/ Telematics Transceiver

Result

Result	Proceed to
OK	A
NG (Central gateway ECU [network gateway ECU] CAN main wire)	B
NG (No. 21 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 1 CAN JUNCTION CONNECTOR

CHECK FOR SHORT IN CAN BUS WIRES (NO. 21 CAN JUNCTION CONNECTOR) Click here

GO TO STEP 5 Click here

CHECK FOR SHORT IN CAN BUS WIRES (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 1 CAN JUNCTION CONNECTOR)

Reconnect the G119 No. 1 CAN junction connector.
Disconnect the G66 central gateway ECU (network gateway ECU) connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
G66-6 (CA3H) - G66-21 (CA3L)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω

Result

Proceed to
OK
NG

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 1 CAN JUNCTION CONNECTOR)

CHECK FOR SHORT IN CAN BUS WIRES (NO. 21 CAN JUNCTION CONNECTOR)

Reconnect the G119 No. 1 CAN junction connector.
Disconnect the L131 No. 21 CAN junction connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
L131-1 (CANH) - L131-7 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	No. 1 CAN junction connector
L131-2 (CANH) - L131-8 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Luggage closer motor assembly
L131-3 (CANH) - L131-9 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Rear multiplex network door ECU LH
L131-4 (CANH) - L131-10 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Stereo component equalizer assembly
L131-5 (CANH) - L131-11 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	No. 7 CAN junction terminal
L131-6 (CANH) - L131-12 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Rear multiplex network door ECU RH

Result

Result	Proceed to
OK	A
NG (No. 7 CAN junction terminal CAN main wire)	B
NG (No. 1 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 21 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 21 CAN JUNCTION CONNECTOR - NO. 1 CAN JUNCTION CONNECTOR)

CHECK FOR SHORT IN CAN BUS WIRES (ECU, SENSOR) Click here

CHECK FOR SHORT IN CAN BUS WIRES (NO. 7 CAN JUNCTION TERMINAL - NO. 21 CAN JUNCTION CONNECTOR)

Reconnect the L131 No. 21 CAN junction connector.
Disconnect the L132 No. 7 CAN junction terminal connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
L132-3 (CANH) - L132-2 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω

Result

Proceed to
OK
NG

REPLACE NO. 7 CAN JUNCTION TERMINAL

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 7 CAN JUNCTION TERMINAL - NO. 21 CAN JUNCTION CONNECTOR)

CHECK FOR SHORT IN CAN BUS WIRES (ECU, SENSOR)

*a
Component with harness connected

(Central Gateway ECU [Network Gateway ECU])

Reconnect all wire harness connectors.
Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited branch line is connected.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
G66-6 (CA3H) - G66-21 (CA3L)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

Tech Tips

If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.

Result

Proceed to
OK
NG

REPLACE ECU OR SENSOR

REPAIR OR REPLACE HARNESS OR CONNECTOR