CAN COMMUNICATION SYSTEM Check Chassis Local Bus 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 19 (CAYH) and 20 (CAYL) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom	Trouble Area
The resistance between terminals 19 (CAYH) and 20 (CAYL) 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) Rear steering control ECU1 Absorber control ECU Front steering control ECU2 Driving support ECU assembly*3 Rack and pinion power steering gear assembly Skid control ECU assembly No. 8 CAN junction connector No. 17 CAN junction connector No. 18 CAN junction connector No. 1 CAN junction terminal

Symptom

Trouble Area

The resistance between terminals 19 (CAYH) and 20 (CAYL) 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)
Rear steering control ECU*1
Absorber control ECU
Front steering control ECU*2
Driving support ECU assembly*3
Rack and pinion power steering gear assembly
Skid control ECU assembly
No. 8 CAN junction connector
No. 17 CAN junction connector
No. 18 CAN junction connector
No. 1 CAN junction terminal

*1: w/ Dynamic Rear Steering System
*2: w/ Variable Gear Ratio Steering System
*3: w/ Pre-collision System

WIRING DIAGRAM

for LHD
for RHD

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 engine 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 engine 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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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 engine 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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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 TERMINAL - NO. 8 CAN JUNCTION CONNECTOR)

Disconnect the cable from the negative (-) battery terminal.
*a
Front view of wire harness connector

(to No. 1 CAN Junction Terminal)

Disconnect the No. 1 CAN junction terminal connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
P131-3 (CANP) - P131-2 (CANN)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

Result

Result	Proceed to
OK	A
NG (for LHD)	B
NG (for RHD)	C

REPLACE NO. 1 CAN JUNCTION TERMINAL

CONNECT CONNECTOR Click here

CONNECT CONNECTOR

Reconnect the P131 No. 1 CAN junction terminal connector.

Result

Proceed to
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 17 CAN JUNCTION CONNECTOR)

*a
Front view of wire harness connector

(to Central Gateway ECU [Network Gateway ECU])

Disconnect the 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
P59-19 (CAYH) - P59-20 (CAYL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

Result

Result
OK
NG

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

CONNECT CONNECTOR

Reconnect the P59 central gateway ECU (network gateway ECU) connector.

Result

Proceed to
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (NO. 17 CAN JUNCTION CONNECTOR)

*a	Front view of wire harness connector (to No. 17 CAN Junction Connector)
*b	to No. 18 CAN Junction Connector
*c	to Absorber Control ECU
*d	to Central Gateway ECU (Network Gateway ECU)

Disconnect the No. 17 CAN junction connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
X114-1 (CANH) - X114-12 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 18 CAN junction connector
X114-2 (CANH) - X114-13 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Absorber control ECU
X114-3 (CANH) - X114-14 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Central gateway ECU (network gateway ECU)

Result

Result	Proceed to
OK	A
NG (Central gateway ECU [network gateway ECU] CAN main wire)	B
NG (No. 18 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 17 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 17 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU])

GO TO STEP 18 Click here

CONNECT CONNECTOR

Reconnect the X114 No. 17 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (NO. 18 CAN JUNCTION CONNECTOR)

*a	Front view of wire harness connector (to No. 18 CAN Junction Connector)
*b	to No. 17 CAN Junction Connector
*c	to Rear Steering Control ECU (w/ Dynamic Rear Steering System)
*d	to No. 8 CAN Junction Connector

Disconnect the No. 18 CAN junction connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
b10-9 (CANH) - b10-20 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 17 CAN junction connector
b10-10 (CANH) - b10-21 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rear steering control ECU*
b10-11 (CANH) - b10-22 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 8 CAN junction connector

*: w/ Dynamic Rear Steering System

Result

Result	Proceed to
OK	A
NG (No. 17 CAN junction connector CAN main wire)	B
NG (No. 8 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 18 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 18 CAN JUNCTION CONNECTOR - NO. 17 CAN JUNCTION CONNECTOR)

GO TO STEP 18 Click here

CONNECT CONNECTOR

Reconnect the b10 No. 18 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (NO. 8 CAN JUNCTION CONNECTOR)

Tech Tips

Before disconnecting the connectors, make a note of where it is connected.
Reconnect the connector to its original position.

Disconnect the No. 8 CAN junction connectors.

No. 8 CAN Junction Connector

Rear view of wire harness connector

(to No. 8 CAN Junction Connector)

Wiring Color
Code	Color (CANH Side)	Color (CANL Side)	Connect to
P125	Y	W	Skid control ECU assembly
P126	B	W	Rack and pinion power steering gear assembly
P127	P	W	Front steering control ECU*1
P128	G	W	No. 18 CAN junction connector
P129	R	W	No. 1 CAN junction terminal
P130	BE	W	Driving support ECU assembly*2

*1: w/ Variable Gear Ratio Steering System

*2: w/ Pre-collision System

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
P125-1 (CANH) - P125-2 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Skid control ECU assembly
P126-1 (CANH) - P126-2 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rack and pinion power steering gear assembly
P127-1 (CANH) - P127-2 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Front steering control ECU*1
P128-1 (CANH) - P128-2 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 18 CAN junction connector
P129-1 (CANH) - P129-2 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 1 CAN junction terminal
P130-1 (CANH) - P130-2 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Driving support ECU assembly*2

*1: w/ Variable Gear Ratio Steering System
*2: w/ Pre-collision System

Result

Result	Proceed to
OK	A
NG (No. 18 CAN junction connector CAN main wire)	B
NG (No. 1 CAN junction terminal CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 8 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 18 CAN JUNCTION CONNECTOR)

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 1 CAN JUNCTION TERMINAL)

GO TO STEP 18 Click here

CONNECT CONNECTOR

Reconnect the P131 No. 1 CAN junction terminal connector.

Result

Proceed to
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 18 CAN JUNCTION CONNECTOR)

*a
Front view of wire harness connector

(to Central Gateway ECU [Network Gateway ECU])

Disconnect the 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
P59-19 (CAYH) - P59-20 (CAYL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

Result

Result
OK
NG

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

CONNECT CONNECTOR

Reconnect the P59 central gateway ECU (network gateway ECU) connector.

Result

Proceed to
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (NO. 18 CAN JUNCTION CONNECTOR)

*a	Front view of wire harness connector (to No. 18 CAN Junction Connector)
*b	to No. 17 CAN Junction Connector
*c	to Rear Steering Control ECU (w/ Dynamic Rear Steering System)
*d	to Central Gateway ECU (Network Gateway ECU)

Disconnect the No. 18 CAN junction connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
b10-9 (CANH) - b10-20 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 17 CAN junction connector
b10-10 (CANH) - b10-21 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rear steering control ECU*
b10-11 (CANH) - b10-22 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Central gateway ECU (network gateway ECU)

*: w/ Dynamic Rear Steering System

Result

Result	Proceed to
OK	A
NG (Central gateway ECU [network gateway ECU] CAN main wire)	B
NG (No. 17 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 18 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 18 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU])

GO TO STEP 18 Click here

CONNECT CONNECTOR

Reconnect the b10 No. 18 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (NO. 17 CAN JUNCTION CONNECTOR)

*a	Front view of wire harness connector (to No. 17 CAN Junction Connector)
*b	to No. 18 CAN Junction Connector
*c	to Absorber Control ECU
*d	to No. 8 CAN Junction Connector

Disconnect the No. 17 CAN junction connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
X114-1 (CANH) - X114-12 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 18 CAN junction connector
X114-2 (CANH) - X114-13 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Absorber control ECU
X114-3 (CANH) - X114-14 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 8 CAN junction connector

Result

Result	Proceed to
OK	A
NG (No. 18 CAN junction connector CAN main wire)	B
NG (No. 8 CAN junction connector CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 17 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 17 CAN JUNCTION CONNECTOR - NO. 18 CAN JUNCTION CONNECTOR)

GO TO STEP 18 Click here

CONNECT CONNECTOR

Reconnect the X114 No. 17 CAN junction connector.

Result

Proceed to
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (NO. 8 CAN JUNCTION CONNECTOR)

Tech Tips

Before disconnecting the connectors, make a note of where it is connected.
Reconnect the connector to its original position.

Disconnect the No. 8 CAN junction connectors.

No. 8 CAN Junction Connector

Rear view of wire harness connector

(to No. 8 CAN Junction Connector)

Wiring Color
Code	Color (CANH Side)	Color (CANL Side)	Connect to
P125	Y	W	Skid control ECU assembly
P126	B	W	Rack and pinion power steering gear assembly
P127	P	W	Front steering control ECU*1
P128	G	W	No. 17 CAN junction connector
P129	R	W	No. 1 CAN junction terminal
P130	BE	W	Driving support ECU assembly*2

*1: w/ Variable Gear Ratio Steering System

*2: w/ Pre-collision System

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
P125-1 (CANH) - P125-2 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Skid control ECU assembly
P126-1 (CANH) - P126-2 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Rack and pinion power steering gear assembly
P127-1 (CANH) - P127-2 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Front steering control ECU*1
P128-1 (CANH) - P128-2 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 17 CAN junction connector
P129-1 (CANH) - P129-2 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 1 CAN junction terminal
P130-1 (CANH) - P130-2 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Driving support ECU assembly*2

*1: w/ Variable Gear Ratio Steering System
*2: w/ Pre-collision System

Result

Result	Proceed to
OK	A
NG (No. 17 CAN junction connector CAN main wire)	B
NG (No. 1 CAN junction terminal CAN main wire)	C
NG (Wire to ECU or sensor)	D

REPLACE NO. 8 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 17 CAN JUNCTION CONNECTOR)

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 1 CAN JUNCTION TERMINAL)

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.

Click here

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

Standard Resistance

Tester Connection	Condition	Specified Condition
P59-19 (CAYH) - P59-20 (CAYL)	Cable disconnected from negative (-) 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

Result
OK
NG

REPLACE ECU OR SENSOR

REPAIR OR REPLACE HARNESS OR CONNECTOR