CAN COMMUNICATION SYSTEM(w/ Central Gateway ECU) Check Bus 2 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 18 (CA4H) of the central gateway ECU and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU and terminal 4 (CG) of the DLC3.

Symptom	Trouble Area
No resistance exists between terminal 18 (CA4H) of the central gateway ECU and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU and terminal 4 (CG) of the DLC3.	Short to ground in bus 2 main lines Short to ground in bus 2 branch lines Combination meter assembly Steering sensor Headlight leveling ECU (headlight swivel ECU assembly) Power steering ECU with motor assembly Main body ECU (Multiplex network body ECU) Airbag sensor assembly Certification ECU (Smart key ECU assembly) Clearance warning ECU assembly Brake actuator assembly (Skid control ECU) Central gateway ECU Air conditioning amplifier assembly ECM Engine stop and start ECU* CAN junction connector LH1 CAN junction connector RH1

Symptom

Trouble Area

No resistance exists between terminal 18 (CA4H) of the central gateway ECU and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU and terminal 4 (CG) of the DLC3.

Short to ground in bus 2 main lines
Short to ground in bus 2 branch lines
Combination meter assembly
Steering sensor
Headlight leveling ECU (headlight swivel ECU assembly)
Power steering ECU with motor assembly
Main body ECU (Multiplex network body ECU)
Airbag sensor assembly
Certification ECU (Smart key ECU assembly)
Clearance warning ECU assembly
Brake actuator assembly (Skid control ECU)
Central gateway ECU
Air conditioning amplifier assembly
ECM
Engine stop and start ECU*
CAN junction connector LH1
CAN junction connector RH1

*: for 6AR-FSE

WIRING DIAGRAM

CAUTION / NOTICE / HINT

Note

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 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: Drive the vehicle at a speed of 36 km/h (22 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 Click here.
If the main body ECU (multiplex network body ECU) is replaced, refer to Service Bulletin.

Tech Tips

Operating the engine 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 the 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 SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU)

Disconnect the cable from the negative (-) battery terminal.
Text in Illustration

*a
Front view of wire harness connector

(to Central Gateway ECU)

Disconnect the H193 central gateway ECU connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H193-18 (CA4H) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H193-17 (CA4L) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Result

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

REPLACE CENTRAL GATEWAY ECU Click here

CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU BRANCH LINE) Click here

CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU BRANCH LINE)

Text in Illustration
*a	Rear view of wire harness connector (to CAN Junction Connector RH1)
*b	to Central Gateway ECU

Disconnect the H129 central gateway ECU branch line connector.

Tech Tips

Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
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.

Text in Illustration
*a	Front view of wire harness connector (to Central Gateway ECU)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H193-18 (CA4H) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H193-17 (CA4L) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO CENTRAL GATEWAY ECU

CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN J/C LH1)

Reconnect the H129 central gateway ECU branch line connector.

Disconnect the H213 CAN junction connector LH1.

Text in Illustration
*1	DLC3	-	-
*a	Front view of wire harness connector (to CAN Junction Connector LH1)	*b	to Headlight Leveling ECU (Headlight Swivel ECU Assembly)
*c	to Engine Stop and Start ECU (for 6AR-FSE)	*d	to Steering Sensor
*e	to Main Body ECU (Multiplex Network Body ECU)	*f	to Airbag Sensor Assembly
*g	to Combination Meter Assembly	*h	to CAN Junction Connector RH1
*i	to Power Steering ECU with Motor Assembly	-	-

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
H213-1 (CANH) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Headlight leveling ECU (headlight swivel ECU assembly)
H213-11 (CANL) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Headlight leveling ECU (headlight swivel ECU assembly)
H213-3 (CANH) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Engine stop and start ECU*
H213-13 (CANL) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Engine stop and start ECU*
H213-4 (CANH) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Steering sensor
H213-14 (CANL) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Steering sensor
H213-5 (CANH) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Main body ECU (multiplex network body ECU)
H213-15 (CANL) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Main body ECU (multiplex network body ECU)
H213-7 (CANH) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Airbag sensor assembly
H213-17 (CANL) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Airbag sensor assembly
H213-8 (CANH) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Combination meter assembly
H213-18 (CANL) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Combination meter assembly
H213-9 (CANH) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	CAN junction connector RH1
H213-19 (CANL) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	CAN junction connector RH1
H213-10 (CANH) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Power steering ECU with motor assembly
H213-20 (CANL) - H29-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Power steering ECU with motor assembly

*: for 6AR-FSE

Result

Symptom	Proceed to
OK	A
NG (CAN junction connector RH1 main lines)	B
NG (ECU or sensor CAN bus lines)	C

REPLACE CAN JUNCTION CONNECTOR LH1

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

CHECK FOR SHORT TO GND IN CAN BUS LINE

Reconnect the H213 CAN junction connector LH1.
Text in Illustration

*a
Front view of wire harness connector

(to Central Gateway ECU)

Connect the probes of an electrical tester to terminals 18 (CA4H) and 10 (GND), or between terminals 17 (CA4L) and 10 (GND) of the H193 central gateway ECU connector.

While observing the resistance value shown on the electrical tester, disconnect connectors (H123, H125, H126, H127 and H132) from the CAN junction connector RH1 one by one until the resistance becomes normal (200 Ω or higher).

Tech Tips

Disconnect the bus line connectors other than those of the central gateway ECU and CAN main bus lines between the CAN junction connector LH1 and CAN junction connector RH1.
Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
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.

Text in Illustration
*a	Component without harness connected (CAN Junction Connector RH1)	-	-

Wiring Color
CAN Junction Connector RH1 Side	Code	Color (CANH Side)	Color (CANL Side)
ECM	H125	B	W
CAN main bus line (bus line connecting CAN junction connector RH1 and CAN junction connector LH1)	H122	R	W
Air conditioning amplifier assembly	H123	G	W
Central gateway ECU	H129	BE	W
Brake actuator assembly (skid control ECU)	H126	Y	W
Certification ECU (smart key ECU assembly)	H127	V	W
Clearance warning ECU assembly	H132	P	W

Note

Do not reconnect the disconnected connectors until this inspection is complete because there may be a short to GND in 2 or more CAN bus lines.

Result

Symptom	Proceed to
The resistance between terminals 18 (CA4H) and 10 (GND), or the resistance between 17 (CA4L) and 10 (GND) is still below 200 Ω when all the specified connectors are disconnected from the CAN junction connector. (There is a short to GND in the CAN junction connector RH1.)	A
The resistance between terminals 18 (CA4H) and 10 (GND), or the resistance between 17 (CA4L) and 10 (GND) becomes normal (200 Ω or higher) when a connector is disconnected from the CAN junction connector. (There is a short to GND in one of the areas that relates to one or more of the disconnected bus lines.)	B

When there is a short to GND in one or more of the bus lines that connect to an ECU or sensor:
1. Reconnect all of the connectors to the CAN junction connector, except for the one that was disconnected last (the bus line that is shorted to GND). Check that the resistance shown on the electrical tester is normal (200 Ω or higher) to confirm that there is a short to GND in the one bus line only.

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

CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN J/C RH1)

Reconnect all of the connectors to the CAN junction connector RH1.

Text in Illustration
*a	Rear view of wire harness connector (to CAN Junction Connector RH1)
*b	to CAN Junction Connector LH1

Disconnect the H122 CAN main bus line connector.

Tech Tips

Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
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.

Text in Illustration
*a	Front view of wire harness connector (to Central Gateway ECU)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H193-18 (CA4H) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H193-17 (CA4L) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPAIR OR REPLACE CAN MAIN BUS LINE (CAN J/C LH1 - CAN J/C RH1)

REPLACE CAN JUNCTION CONNECTOR RH1

CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU BRANCH LINE)

Text in Illustration
*a	Rear view of wire harness connector (to CAN Junction Connector RH1)
*b	to Central Gateway ECU

Disconnect the H129 central gateway ECU branch line connector.

Tech Tips

Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
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.

Text in Illustration
*a	Front view of wire harness connector (to Central Gateway ECU)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H193-18 (CA4H) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H193-17 (CA4L) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO CENTRAL GATEWAY ECU

CHECK FOR SHORT TO GND IN CAN BUS LINE

Reconnect the H129 central gateway ECU branch line connector.
Text in Illustration

*a
Front view of wire harness connector

(to Central Gateway ECU)

Connect the probes of an electrical tester to terminals 18 (CA4H) and 10 (GND), or between terminals 17 (CA4L) and 10 (GND) of the H193 central gateway ECU connector.

While observing the resistance value shown on the electrical tester, disconnect connectors (H117, H118, H120, H123, H125, H126, H127, H132, H167, H211 and H214) from the CAN junction connector LH1 and CAN junction connector RH1 one by one until the resistance becomes normal (200 Ω or higher).

Tech Tips

Disconnect the ECU and sensor connectors other than the central gateway ECU branch lines and CAN main bus lines between the CAN junction connector LH1 and CAN junction connector RH1.
Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
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.

Text in Illustration
*1	Clearance Warning ECU Assembly	*2	Steering Sensor
*3	Certification ECU (Smart Key ECU Assembly)	*4	Central Gateway ECU
*5	Combination Meter Assembly	*6	Headlight Leveling ECU (Headlight Swivel ECU Assembly)
*7	Brake Actuator Assembly (Skid Control ECU)	*8	Air Conditioning Amplifier Assembly
*9	Power Steering ECU with Motor Assembly	*10	ECM
*11	Airbag Sensor Assembly	*12	Main Body ECU (Multiplex Network Body ECU)
*13	CAN Junction Connector RH1	*14	CAN Junction Connector LH1

Text in Illustration
*a	Component without harness connected (CAN Junction Connector LH1)	-	-

Wiring Color
CAN Junction Connector LH1 Side	Code	Color (CANH Side)	Color (CANL Side)
CAN main bus line (bus line connecting CAN junction connector LH1 and CAN junction connector RH1)	H116	R	W
Air conditioning amplifier assembly	H123	G	W
ECM	H125	L	W
Airbag sensor assembly	H211	Y	W
Main body ECU (multiplex network body ECU)	H118	V	W
Power steering ECU with motor assembly	H167	P	W

Text in Illustration
*a	Component without harness connected (CAN Junction Connector RH1)	-	-

Wiring Color
CAN Junction Connector RH1 Side	Code	Color (CANH Side)	Color (CANL Side)
Steering sensor	H120	BE	W
Clearance warning ECU assembly	H132	P	W
Certification ECU (smart key ECU assembly)	H127	V	W
Central gateway ECU	H129	Y	W
Headlight leveling ECU (headlight swivel ECU assembly)	H214	L	W
Combination meter assembly	H117	G	W
CAN main bus line (bus line connecting CAN junction connector LH1 and CAN junction connector RH1)	H122	R	W
Brake actuator assembly (skid control ECU)	H126	B	W

Note

Do not reconnect the disconnected connectors until this inspection is complete because there may be a short to GND in 2 or more CAN bus lines.

Result

Symptom	Proceed to
The resistance between terminals 18 (CA4H) and 10 (GND), or the resistance between 17 (CA4L) and 10 (GND) is still below 200 Ω when all the specified connectors are disconnected from the CAN junction connector. (There is a short to GND in the CAN main bus lines between the CAN junction connector LH1 and CAN junction connector RH1.)	A
The resistance between terminals 18 (CA4H) and 10 (GND), or the resistance between 17 (CA4L) and 10 (GND) becomes normal (200 Ω or higher) when a connector is disconnected from the CAN junction connector. (There is a short to GND in one of the areas that relates to one or more of the disconnected bus lines.)	B

When there is a short to GND in one or more of the bus lines that connect to an ECU or sensor:
1. Reconnect all of the connectors to the CAN junction connector, except for the one that was disconnected last (the bus line that is shorted to GND). Check that the resistance shown on the electrical tester is normal (200 Ω or higher) to confirm that there is a short to GND in the one bus line only.
When there is no short to GND in any of the bus lines that connect to the ECUs and sensors:
1. With all the specified connectors for ECUs and sensors disconnected, proceed with the inspection of the CAN main bus lines between the CAN junction connector LH1 and CAN junction connector RH1.

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

CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN J/C RH1)

Reconnect all of the connectors to the CAN junction connector LH1 and CAN junction connector RH1.

Text in Illustration
*a	Rear view of wire harness connector (to CAN Junction Connector RH1)
*b	to CAN Junction Connector LH1

Disconnect the H122 CAN main bus line connector.

Tech Tips

Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
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.

Text in Illustration
*a	Front view of wire harness connector (to Central Gateway ECU)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H193-18 (CA4H) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H193-17 (CA4L) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPLACE CAN JUNCTION CONNECTOR RH1

CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN J/C LH1 - CAN J/C RH1)

Reconnect the H122 CAN main bus line connector.

Text in Illustration
*a	Rear view of wire harness connector (to CAN Junction Connector LH1)
*b	to CAN Junction Connector RH1

Disconnect the H116 CAN main bus line connector.

Tech Tips

Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
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.

Text in Illustration
*a	Front view of wire harness connector (to Central Gateway ECU)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H193-18 (CA4H) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H193-17 (CA4L) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPLACE CAN JUNCTION CONNECTOR LH1

REPAIR OR REPLACE CAN MAIN BUS LINE (CAN J/C LH1 - CAN J/C RH1)

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

Reconnect all of the connectors to the CAN junction connector LH1 and CAN junction connector RH1.
Text in Illustration

*a
Front view of wire harness connector

(to Central Gateway ECU)

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.

Standard Resistance

Tester Connection	Condition	Specified Condition
H193-18 (CA4H) - H193-10 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H193-17 (CA4L) - H193-10 (GND)	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.

REPLACE CORRESPONDING ECU OR SENSOR

REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BUS LINE OR CONNECTOR