CAN COMMUNICATION SYSTEM Check Bus 5 Line for Short to GND

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom	Trouble Area
There is no resistance between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.	Short to ground in CAN main bus line Short to ground in CAN branch line Central gateway ECU (network gateway ECU) Headlight ECU sub-assembly LH Headlight ECU sub-assembly RH Outer mirror control ECU assembly (for driver side) (w/ Seat Position Memory System) Outer mirror control ECU assembly (for front passenger side) (w/ Seat Position Memory System) Position control ECU assembly RH (w/ Seat Position Memory System) Multiplex tilt and telescopic ECU (w/ Power Tilt and Power Telescopic System) Air conditioning amplifier assembly Certification ECU (smart key ECU assembly) (w/ Smart Entry and Start System) Main body ECU (multiplex network body ECU) Combination meter assembly Meter mirror sub-assembly (w/ Headup Display System) No. 3 CAN junction connector No. 1 junction connector No. 2 junction connector No. 5 junction connector (for RHD) No. 6 junction connector (for LHD)

Symptom

Trouble Area

There is no resistance between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Short to ground in CAN main bus line
Short to ground in CAN branch line
Central gateway ECU (network gateway ECU)
Headlight ECU sub-assembly LH
Headlight ECU sub-assembly RH
Outer mirror control ECU assembly (for driver side)

(w/ Seat Position Memory System)
Outer mirror control ECU assembly (for front passenger side)

(w/ Seat Position Memory System)
Position control ECU assembly RH

(w/ Seat Position Memory System)
Multiplex tilt and telescopic ECU

(w/ Power Tilt and Power Telescopic System)
Air conditioning amplifier assembly
Certification ECU (smart key ECU assembly)

(w/ Smart Entry and Start System)
Main body ECU (multiplex network body ECU)
Combination meter assembly
Meter mirror sub-assembly

(w/ Headup Display System)
No. 3 CAN junction connector
No. 1 junction connector
No. 2 junction connector
No. 5 junction connector

(for RHD)
No. 6 junction connector

(for LHD)

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.

Click here
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.

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 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.

Click here
Before replacing the main body ECU (multiplex network body ECU) or certification ECU (smart key ECU assembly), refer to Service Bulletin.

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 TO GND IN CAN BUS LINE (NO. 3 CAN JUNCTION CONNECTOR)

Disconnect the cable from the negative (-) battery terminal.
Disconnect the K126 No. 3 CAN junction connector.

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

*1	DLC3	-	-
*a	Front view of wire harness connector (to No. 3 CAN Junction Connector)	*b	to No. 1 Junction Connector
*c	to Certification ECU (Smart Key ECU Assembly) (w/ Smart Entry and Start System)	*d	to Combination Meter Assembly
*e	to Main Body ECU (Multiplex Network Body ECU)	*f	to Air Conditioning Amplifier Assembly
*g	to Headlight ECU Sub-assembly LH	*h	to Meter Mirror Sub-assembly (w/ Headup Display System)
*i	to Multiplex Tilt and Telescopic ECU (w/ Power Tilt and Power Telescopic System)	-	-

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
K126-3 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 junction connector
K126-14 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 junction connector
K126-4 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Certification ECU (smart key ECU assembly)*1
K126-15 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Certification ECU (smart key ECU assembly)*1
K126-5 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Combination meter assembly
K126-16 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Combination meter assembly
K126-6 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Main body ECU (multiplex network body ECU)
K126-17 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Main body ECU (multiplex network body ECU)
K126-7 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Air conditioning amplifier assembly
K126-18 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Air conditioning amplifier assembly
K126-8 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Headlight ECU sub-assembly LH
K126-19 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Headlight ECU sub-assembly LH
K126-9 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Meter mirror sub-assembly*2
K126-20 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Meter mirror sub-assembly*2
K126-10 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Multiplex tilt and telescopic ECU*3
K126-21 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Multiplex tilt and telescopic ECU*3

*1: w/ Smart Entry and Start System
*2: w/ Headup Display System
*3: w/ Power Tilt and Power Telescopic System

Result

Result	Proceed to
OK	A
NG (Line to No. 1 junction connector)	B
NG (Line to ECU or sensor)	C

REPLACE NO. 3 CAN JUNCTION CONNECTOR

GO TO STEP 7 Click here

CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 1 JUNCTION CONNECTOR)

Disconnect the R94 No. 1 junction connector.

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

*1	DLC3	-	-
*a	Front view of wire harness connector (to No. 1 Junction Connector)	*b	to Outer Mirror Control ECU Assembly (for Front Passenger Side) (w/ Seat Position Memory System)
*c	to No. 3 CAN Junction Connector	*d	to No. 5 Junction Connector (for RHD)
*e	to No. 6 Junction Connector (for LHD)	-	-

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
R94-1 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Outer mirror control ECU assembly (for front passenger side)*1
R94-12 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
R94-3 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 3 CAN junction connector
R94-14 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 3 CAN junction connector
R94-4 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 5 junction connector*2
R94-15 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 5 junction connector*2
R94-4 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 6 junction connector*3
R94-15 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 6 junction connector*3

*1: w/ Seat Position Memory System
*2: for RHD
*3: for LHD

Result

Result	Proceed to
OK	A
NG (Line to No. 3 CAN junction connector)	B
NG (Line to No. 5 junction connector (for RHD))	C
NG (Line to No. 6 junction connector (for LHD))	D
NG (Line to ECU or sensor)	E

REPLACE NO. 1 JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 1 JUNCTION CONNECTOR - NO. 3 CAN JUNCTION CONNECTOR)

CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 6 JUNCTION CONNECTOR) Click here

GO TO STEP 7 Click here

CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 5 JUNCTION CONNECTOR)

Disconnect the R100 No. 5 junction connector.

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

DLC3

Front view of wire harness connector

(to No. 5 Junction Connector)

to No. 2 Junction Connector

to No. 1 Junction Connector

to Position Control ECU Assembly RH

(w/ Seat Position Memory System)

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
R100-5 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 2 junction connector
R100-16 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 2 junction connector
R100-6 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 junction connector
R100-17 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 junction connector
R100-7 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Position control ECU assembly RH*
R100-18 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Position control ECU assembly RH*

*: w/ Seat Position Memory System

Result

Result	Proceed to
OK	A
NG (Line to No. 1 junction connector)	B
NG (Line to No. 2 junction connector)	C
NG (Line to ECU or sensor)	D

REPLACE NO. 5 JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 5 JUNCTION CONNECTOR - NO. 1 JUNCTION CONNECTOR)

GO TO STEP 5 Click here

GO TO STEP 7 Click here

CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 6 JUNCTION CONNECTOR)

Disconnect the R101 No. 6 junction connector.

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

DLC3

Front view of wire harness connector

(to No. 6 Junction Connector)

to No. 2 Junction Connector

to No. 1 Junction Connector

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
R101-1 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 2 junction connector
R101-12 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 2 junction connector
R101-2 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 junction connector
R101-13 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 1 junction connector

Result

Result	Proceed to
OK	A
NG (Line to No. 1 junction connector)	B
NG (Line to No. 2 junction connector)	C

REPLACE NO. 6 JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 6 JUNCTION CONNECTOR - NO. 1 JUNCTION CONNECTOR)

CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 2 JUNCTION CONNECTOR)

Disconnect the R97 No. 2 junction connector.

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

*1	DLC3	-	-
*a	Front view of wire harness connector (to No. 2 Junction Connector)	*b	to Central Gateway ECU (Network Gateway ECU)
*c	to No. 5 Junction Connector (for RHD)	*d	to No. 6 Junction Connector (for LHD)
*e	to Outer Mirror Control ECU Assembly (for Driver Side) (w/ Seat Position Memory System)	*f	to Headlight ECU Sub-assembly RH

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
R97-1 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Central gateway ECU (network gateway ECU)
R97-12 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Central gateway ECU (network gateway ECU)
R97-2 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 5 junction connector*1
R97-13 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 5 junction connector*1
R97-2 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 6 junction connector*2
R97-13 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	No. 6 junction connector*2
R97-3 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Outer mirror control ECU assembly (for driver side)*3
R97-14 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Outer mirror control ECU assembly (for driver side)*3
R97-5 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Headlight ECU sub-assembly RH
R97-16 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Headlight ECU sub-assembly RH

*1: for RHD
*2: for LHD
*3: w/ Seat Position Memory System

Result

Result	Proceed to
OK	A
NG (Line to No. 5 junction connector (for RHD))	B
NG (Line to No. 6 junction connector (for LHD))	C
NG (Line to central gateway ECU (network gateway ECU))	D
NG (Line to ECU or sensor)	E

REPLACE NO. 2 JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 2 JUNCTION CONNECTOR - NO. 5 JUNCTION CONNECTOR)

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 2 JUNCTION CONNECTOR - NO. 6 JUNCTION CONNECTOR)

CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU OR SENSOR) Click here

CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 2 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

Disconnect the K76 central gateway ECU (network gateway ECU) connector.

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

DLC3

Front view of wire harness connector

(to No. 2 Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance

Tester Connection	Condition	Specified Condition
R97-1 (CANH) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
R97-12 (CANL) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Result

Result
OK
NG

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 2 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU OR SENSOR)

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

Click here

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

DLC3

Component with harness connected

(Central Gateway ECU (Network Gateway ECU))

Standard Resistance

Tester Connection	Condition	Specified Condition
K76-15 (CA5H) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
K76-16 (CA5L) - K68-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Tech Tips

If the resistance changes to 200 Ω or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
If the resistance does not become normal when the connector is disconnected from the ECU or sensor, check for a short to ground in the wire harness and repair or replace the wire harness or connector if necessary.

Result

Result
OK
NG

REPLACE ECU OR SENSOR

REPAIR OR REPLACE HARNESS OR CONNECTOR