CAN COMMUNICATION SYSTEM(for RHD), Diagnostic DTC:U1002

DTC Code	DTC Name
U1002	Lost Communication with Gateway Module (Sensor Bus)

DESCRIPTION

The driving support ECU assembly will store this DTC when no signals can be received from the ECUs that have been memorized as those that are connected to local bus.

When the driving support ECU assembly receives a response signal from the ECUs connected to local bus, the driving support ECU assembly recognizes and memorizes that the ECU is connected to local bus. Based on this memorized data, the driving support ECU assembly monitors for malfunctions in the ECUs connected to local bus when communicating with those ECUs. If the driving support ECU assembly cannot receive response signals from the ECUs that have been memorized as those connected to local bus, the driving support ECU assembly determines that a malfunction exists.

DTC Code	DTC Detection Condition	Trouble Area
U1002	Driving support ECU assembly cannot receive signals from all ECUs that have been memorized as those connected to local bus.	Open or short in local bus CAN main wire or connector Open or short in local bus CAN branch wire or connector Driving support ECU assembly Millimeter wave radar sensor assembly Forward recognition camera Headlight ECU Sub-assembly LH Headlight ECU Sub-assembly RH No. 10 CAN junction connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

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 engine 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 engine switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work Click here.
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the engine switch is on (IG) and wait at least 6 seconds.
After the repair, perform 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 engine switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
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.

PROCEDURE

CHECK LOCAL BUS

Text in Illustration
*a	Component with harness connected (Driving Support ECU Assembly)
*B	Front view of DLC3

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

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Resistance: Malfunction
E138-8 (CA1P) - E138-9 (CA1N)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω	Below 53 Ω: Short in line
E138-8 (CA1P) - E138-9 (CA1N)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω	Higher than 70 Ω: Open in CAN main bus line
E138-8 (CA1P) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Below 6 kΩ: +B short
E138-9 (CA1N) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Below 6 kΩ: +B short
E138-8 (CA1P) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Below 200 Ω: Ground short
E138-9 (CA1N) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Below 200 Ω: Ground short

Result
Result	Proceed to
OK	A
NG (Open circuit in CAN main bus wire)	B
NG (Short circuit between bus wire)	C
NG Ground short +B short	D

CHECK FOR OPEN IN CAN BUS MAIN WIRE (FORWARD RECOGNITION CAMERA) Click here

CHECK FOR SHORT IN CAN BUS WIRES (FORWARD RECOGNITION CAMERA) Click here

CHECK FOR DTC OUTPUT
1. Clear the DTCs Click here.
2. Recheck for DTCs and check that no DTCs are output Click here.
  
  OK
  
  DTC U1002 is not output.
OK
USE SIMULATION METHOD TO CHECK Click here

NG
REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

OK
DTC U1002 is not output.

CHECK FOR OPEN IN CAN BUS MAIN WIRE (FORWARD RECOGNITION CAMERA)

Text in Illustration

*a
Front view of wire harness connector

(to Forward Recognition Camera)

Disconnect the forward recognition camera connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
R15-6 (CANH) - R15-12 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE FORWARD RECOGNITION CAMERA Click here

CONNECT CONNECTOR
1. Reconnect the R15 forward recognition camera connector.
NEXT

CHECK FOR OPEN IN CAN BUS MAIN WIRE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

Text in Illustration

*a
Front view of wire harness connector

(to Millimeter Wave Radar Sensor Assembly)

Disconnect the millimeter wave radar sensor assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
A67-5 (CA1P) - A67-6 (CA1N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

CONNECT CONNECTOR
1. Reconnect the A67 millimeter wave radar sensor assembly connector.
NEXT

CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 10 CAN JUNCTION CONNECTOR)

Disconnect the No. 10 CAN junction connector.

Text in Illustration
*a	Front view of wire harness connector (to No. 10 CAN Junction Connector)	*b	to Millimeter Wave Radar Sensor Assembly
*c	to Forward Recognition Camera	-	-

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connect to
E164-5 (CANH) - E164-15 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Millimeter wave radar sensor assembly
E164-6 (CANH) - E164-16 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Forward recognition camera

Result
Result	Proceed to
OK	A
NG (Millimeter wave radar sensor assembly CAN main wire)	B
NG (Forward recognition camera CAN main wire)	C

REPLACE NO. 10 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 10 CAN JUNCTION CONNECTOR - MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 10 CAN JUNCTION CONNECTOR - FORWARD RECOGNITION CAMERA)

CHECK FOR SHORT IN CAN BUS WIRES (FORWARD RECOGNITION CAMERA)

Text in Illustration

*a
Front view of wire harness connector

(to Forward Recognition Camera)

Disconnect the forward recognition camera connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
R15-6 (CANH) - R15-12 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE FORWARD RECOGNITION CAMERA Click here

CONNECT CONNECTOR
1. Reconnect the R15 forward recognition camera connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

Text in Illustration

*a
Front view of wire harness connector

(to Millimeter Wave Radar Sensor Assembly)

Disconnect the millimeter wave radar sensor assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
A67-5 (CA1P) - A67-6 (CA1N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

CONNECT CONNECTOR
1. Reconnect the A67 millimeter wave radar sensor assembly connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (NO. 10 CAN JUNCTION CONNECTOR)

Disconnect the No. 10 CAN junction connector.

Text in Illustration
*a	Front view of wire harness connector (to No. 10 CAN Junction Connector)	*b	to Headlight ECU Sub-assembly LH
*c	to Headlight ECU Sub-assembly RH	*d	to Millimeter Wave Radar Sensor Assembly
*e	to Forward Recognition Camera	*f	to Driving Support ECU Assembly

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connect to
E164-3 (CANH) - E164-13 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Headlight ECU sub-assembly LH
E164-4 (CANH) - E164-14 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Headlight ECU sub-assembly RH
E164-5 (CANH) - E164-15 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Millimeter wave radar sensor assembly
E164-6 (CANH) - E164-16 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Forward recognition camera
E164-7 (CANH) - E164-17 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Driving support ECU assembly

Result
Result	Proceed to
OK	A
NG (Millimeter wave radar sensor assembly CAN main wire)	B
NG (Forward recognition camera CAN main wire)	C
NG (Driving support ECU assembly CAN branch wire)	D
NG (ECU or sensor CAN branch wires)	E

REPLACE NO. 10 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 10 CAN JUNCTION CONNECTOR - MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 10 CAN JUNCTION CONNECTOR - FORWARD RECOGNITION CAMERA)

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

CONNECT CONNECTOR
1. Reconnect the E164 No. 10 CAN junction connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (DRIVING SUPPORT ECU ASSEMBLY)

Text in Illustration

*a
Front view of wire harness connector

(to Driving Support ECU Assembly)

Disconnect the driving support ECU assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
E138-8 (CA1P) - E138-9 (CA1N)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - NO. 10 CAN JUNCTION CONNECTOR)

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

Text in Illustration

*a
Component with harness connected

(Driving Support ECU Assembly)

Reconnect the CAN junction connector.
Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited branch line is connected.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
E138-8 (CA1P) - E138-9 (CA1N)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

REPLACE CORRESPONDING ECU OR SENSOR

REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR CAN BRANCH WIRE OR CONNECTOR

CHECK FOR SHORT IN CAN BUS WIRES (FORWARD RECOGNITION CAMERA)

Text in Illustration
*a	Front view of wire harness connector (to Forward Recognition Camera)
*b	Front view of DLC3

Disconnect the forward recognition camera connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
R15-6 (CANH) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
R15-12 (CANL) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
R15-6 (CANH) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
R15-12 (CANL) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPLACE FORWARD RECOGNITION CAMERA Click here

CONNECT CONNECTOR
1. Reconnect the R15 forward recognition camera connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

Text in Illustration
*a	Front view of wire harness connector (to Millimeter Wave Radar Sensor Assembly)
*b	Front view of DLC3

Disconnect the millimeter wave radar sensor assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
A67-5 (CA1P) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
A67-6 (CA1N) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
A67-5 (CA1P) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
A67-6 (CA1N) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY Click here

CONNECT CONNECTOR
1. Reconnect the A67 millimeter wave radar sensor assembly connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (NO. 10 CAN JUNCTION CONNECTOR)

Disconnect the No. 10 CAN junction connector.

Text in Illustration
*a	Front view of wire harness connector (to No. 10 CAN Junction Connector)	*b	Front view of DLC3
*c	to Headlight ECU Sub-assembly LH	*d	to Headlight ECU Sub-assembly RH
*e	to Millimeter Wave Radar Sensor Assembly	*f	to Forward Recognition Camera
*g	to Driving Support ECU Assembly	-	-

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connect to
E164-3 (CANH) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Headlight ECU sub-assembly LH
E164-13 (CANL) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
E164-3 (CANH) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E164-13 (CANL) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E164-4 (CANH) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Headlight ECU sub-assembly RH
E164-14 (CANL) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
E164-4 (CANH) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E164-14 (CANL) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E164-5 (CANH) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Millimeter wave radar sensor assembly
E164-15 (CANL) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
E164-5 (CANH) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E164-15 (CANL) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E164-6 (CANH) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Forward recognition camera
E164-16 (CANL) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
E164-6 (CANH) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E164-16 (CANL) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E164-7 (CANH) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Driving support ECU assembly
E164-17 (CANL) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
E164-7 (CANH) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E164-17 (CANL) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

Result
Result	Proceed to
OK	A
NG (Millimeter wave radar sensor assembly CAN main wire)	B
NG (Forward recognition camera CAN main wire)	C
NG (Driving support ECU assembly CAN branch wire)	D
NG (ECU or sensor CAN branch wires)	E

REPLACE NO. 10 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 10 CAN JUNCTION CONNECTOR - MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 10 CAN JUNCTION CONNECTOR - FORWARD RECOGNITION CAMERA)

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

CONNECT CONNECTOR
1. Reconnect the E164 No. 10 CAN junction connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (DRIVING SUPPORT ECU ASSEMBLY)

Text in Illustration
*a	Front view of wire harness connector (to Driving Support ECU Assembly)
*b	Front view of DLC3

Disconnect the driving support ECU assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
E138-8 (CA1P) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
E138-9 (CA1N) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
E138-8 (CA1P) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E138-9 (CA1N) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - NO. 10 CAN JUNCTION CONNECTOR)

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

Text in Illustration
*a	Component with harness connected (Driving Support ECU Assembly)
*B	Front view of DLC3

Reconnect the CAN junction connector.

Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the bus line shorted to +B, GND is connected.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
E138-8 (CA1P) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
E138-9 (CA1N) - E22-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
E138-8 (CA1P) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
E138-9 (CA1N) - E22-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher

REPLACE CORRESPONDING ECU OR SENSOR

REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR CAN BRANCH WIRE OR CONNECTOR