CAN COMMUNICATION SYSTEM, Diagnostic DTC:U1002

DTC Code	DTC Name
U1002	Lost Communication with Gateway Module (Power Management2)

DESCRIPTION

The power management control ECU stores this DTC when no signals can be received from the ECUs that have been memorized as those connected to the sub bus 12.
When the power management control ECU receives a response signal from the ECUs connected to the sub bus 12, the power management ECU recognizes and memorizes that the ECU is connected to the sub bus 12. Based on this memorized data, the power management control ECU monitors for malfunctions in the ECUs connected to the sub bus 12 when communicating with those ECUs. If the power management control ECU cannot receive response signals from the ECUs that have been memorized as those connected to the sub bus 12, the power management control ECU determines that a malfunction exists.
If 2 or more DTCs are output during the DTC check, one side of the CAN branch wire may be open (one side of the CANH [CAN branch wire]/CANL [CAN branch wire] of the ECU and/or sensor is open).

DTC Code	DTC Detection Condition	Trouble Area
U1002	Lost communication with the gateway module (Power Management2).	Sub bus 12 circuit Air conditioning amplifier assembly CAN branch wire or connector* Power management control ECU CAN main wire or connector ECM CAN main wire or connector Air conditioning amplifier assembly* Power management control ECU ECM No. 5 CAN junction connector*

For vehicles with a 1WW engine type.
*: w/ Entry and Start System

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 ignition 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 ignition 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.
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 ignition 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 VEHICLE CONDITION

Check the vehicle condition.

Result
Result	Proceed to
w/ Entry and Start System	A
w/o Entry and Start System	B

CHECK FOR OPEN IN CAN BUS WIRE (POWER MANAGEMENT CONTROL ECU CAN MAIN WIRE) Click here

CHECK SUB BUS 12

Text in Illustration

*a
Component with harness connected

(to Power Management Control ECU)

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

Text in Illustration
*a	Component with harness connected (to Power Management Control ECU)

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Resistance: Malfunction
H71-12 (CA3P) - H71-11 (CA3N)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω	Below 53 Ω: Short in line
H71-12 (CA3P) - H71-11 (CA3N)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω	Higher than 70 Ω: Open in CAN main bus line
H71-12 (CA3P) - H71-1 (AM22)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Below 6 kΩ: +B short
H71-11 (CA3N) - H71-1 (AM22)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Below 6 kΩ: +B short
H71-12 (CA3P) - H71-6 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Below 200 Ω: Ground short
H71-11 (CA3N) - H71-6 (GND)	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 wires)	C
NG +B short Ground short	D

CHECK FOR OPEN IN CAN BUS WIRE (NO. 5 CAN JUNCTION CONNECTOR) Click here

CHECK FOR SHORT IN CAN BUS WIRES (NO. 5 CAN JUNCTION CONNECTOR) Click here

CHECK FOR DTC

Clear the DTCs.

Recheck for DTCs and check that no DTCs are output.

OK
DTC U1002 is not output.

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

USE SIMULATION METHOD TO CHECK Click here

REPLACE POWER MANAGEMENT CONTROL ECU Click here

CHECK FOR OPEN IN CAN BUS WIRE (NO. 5 CAN JUNCTION CONNECTOR)

Text in Illustration
*a	Rear view of wire harness connector (to No. 5 CAN Junction Connector)
*b	to ECM
*c	to Power Management Control ECU

Disconnect the No. 5 CAN junction connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
H126-5 (CANH) - H126-16 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	ECM
H126-6 (CANH) - H126-17 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Power management control ECU

Result
Result	Proceed to
OK	A
NG (to ECM CAN main wire)	B
NG (to Power management control ECU CAN main wire)	C

REPLACE NO. 5 CAN JUNCTION CONNECTOR

CONNECT CONNECTOR Click here

CONNECT CONNECTOR
1. Reconnect the H126 No. 5 CAN junction connector.
NEXT

CHECK FOR OPEN IN CAN BUS MAIN WIRE (ECM - NO. 5 CAN JUNCTION CONNECTOR)

Text in Illustration

*a
Front view of wire harness connector

(to ECM)

Disconnect the ECM connector.

Text in Illustration
*a	Front view of wire harness connector (to ECM)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
A76-13 (CANP) - A76-12 (CANN)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE ECM Click here

REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO ECM (ECM - NO. 5 CAN JUNCTION CONNECTOR)

CONNECT CONNECTOR
1. Reconnect the H126 No. 5 CAN junction connector.
NEXT

CHECK FOR OPEN IN CAN BUS MAIN WIRE (POWER MANAGEMENT CONTROL ECU - NO. 5 CAN JUNCTION CONNECTOR)

Text in Illustration

*a
Rear view of wire harness connector

(to Power Management Control ECU)

Disconnect the power management control ECU connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H71-12 (CA3P) - H71-11 (CA3N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

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

REPLACE POWER MANAGEMENT CONTROL ECU Click here

REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO POWER MANAGEMENT CONTROL ECU (POWER MANAGEMENT CONTROL ECU - NO. 5 CAN JUNCTION CONNECTOR)

CHECK FOR SHORT IN CAN BUS WIRES (NO. 5 CAN JUNCTION CONNECTOR)

Disconnect the No. 5 CAN junction connector.

Text in Illustration
*a	Rear view of wire harness connector (to No. 5 CAN Junction Connector)	*b	to ECM
*c	to Power Management Control ECU	*d	to Air Conditioning Amplifier Assembly

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
H126-5 (CANH) - H126-16 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	ECM
H126-6 (CANH) - H126-17 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Power management control ECU
H126-7 (CANH) - H126-18 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Air conditioning amplifier assembly

Result
Result	Proceed to
OK	A
NG (to ECM CAN main wire)	B
NG (to Power management control ECU CAN main wire)	C
NG (ECU or sensor CAN branch wire)	D

REPLACE NO. 5 CAN JUNCTION CONNECTOR

CONNECT CONNECTOR Click here

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

CONNECT CONNECTOR
1. Reconnect the H126 No. 5 CAN junction connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (ECM - NO. 5 CAN JUNCTION CONNECTOR)

Text in Illustration

*a
Front view of wire harness connector

(to ECM)

Disconnect the ECM connector.

Text in Illustration
*a	Front view of wire harness connector (to ECM)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
A76-13 (CANP) - A76-12 (CANN)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE ECM Click here

REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO ECM (ECM - NO. 5 CAN JUNCTION CONNECTOR)

CONNECT CONNECTOR
1. Reconnect the H126 No. 5 CAN junction connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (POWER MANAGEMENT CONTROL ECU - NO. 5 CAN JUNCTION CONNECTOR)

Text in Illustration

*a
Rear view of wire harness connector

(to Power Management Control ECU)

Disconnect the power management control ECU connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H71-12 (CA3P) - H71-11 (CA3N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

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

REPLACE POWER MANAGEMENT CONTROL ECU Click here

REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO POWER MANAGEMENT CONTROL ECU (POWER MANAGEMENT CONTROL ECU - NO. 5 CAN JUNCTION CONNECTOR)

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

Text in Illustration

*a
Component with harness connected

(to Power Management Control ECU)

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.
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
H71-12 (CA3P) - H71-11 (CA3N)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

REPLACE CORRESPONDING ECU OR SENSOR

REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR CAN WIRE OR CONNECTOR

CHECK FOR SHORT IN CAN BUS WIRES (NO. 5 CAN JUNCTION CONNECTOR)

Disconnect the No. 5 CAN junction connector.

Text in Illustration
*a	Rear view of wire harness connector (to No. 5 CAN Junction Connector)	*b	Front view of DLC3
*c	to ECM	*d	to Power Management Control ECU
*e	to Air Conditioning Amplifier Assembly	-	-

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

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
H126-5 (CANH) - H16-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	ECM
H126-16 (CANL) - H16-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H126-5 (CANH) - H16-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
H126-16 (CANL) - H16-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
H126-6 (CANH) - H16-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Power management control ECU
H126-17 (CANL) - H16-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H126-6 (CANH) - H16-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
H126-17 (CANL) - H16-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
H126-7 (CANH) - H16-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Air conditioning amplifier assembly
H126-18 (CANL) - H16-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H126-7 (CANH) - H16-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
H126-18 (CANL) - H16-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

Result
Result	Proceed to
OK	A
NG (to Power management control ECU CAN main wire)	B
NG (ECU or sensor CAN wire)	C

REPLACE NO. 5 CAN JUNCTION CONNECTOR

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

CONNECT CONNECTOR
1. Reconnect the H126 No. 5 CAN junction connector.
NEXT

CHECK FOR SHORT IN CAN BUS WIRES (POWER MANAGEMENT CONTROL ECU - NO.5 CAN JUNCTION CONNECTOR)

Text in Illustration
*a	Rear view of wire harness connector (to Power Management Control ECU)
*b	Front view of DLC3

Disconnect the power management control ECU connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H71-12 (CA3P) - H16-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H71-11 (CA3N) - H16-4 (CG)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H71-12 (CA3P) - H16-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
H71-11 (CA3N) - H16-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

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

REPLACE POWER MANAGEMENT CONTROL ECU Click here

REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO POWER MANAGEMENT CONTROL ECU (POWER MANAGEMENT CONTROL ECU - NO. 5 CAN JUNCTION CONNECTOR)

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

Text in Illustration

*a
Component with harness connected

(to Power Management Control ECU)

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
H71-12 (CA3P) - H71-6 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H71-11 (CA3N) - H71-6 (GND)	Cable disconnected from negative (-) battery terminal	200 Ω or higher
H71-12 (CA3P) - H71-1 (AM22)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
H71-11 (CA3N) - H71-1 (AM22)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

REPLACE CORRESPONDING ECU OR SENSOR

REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR CAN WIRE OR CONNECTOR

CHECK FOR OPEN IN CAN BUS WIRE (POWER MANAGEMENT CONTROL ECU CAN MAIN WIRE)

Text in Illustration

*a
Rear view of wire harness connector

(to Power Management Control ECU)

Disconnect the power management control ECU connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H72-4 (CA3P) - H72-3 (CA3N)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω

REPLACE CAN MAIN WIRE CONNECTED TO POWER MANAGEMENT CONTROL ECU (CA3P, CA3N)

CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - BATTERY AND BODY GROUND)

Text in Illustration

*a
Rear view of wire harness connector

(to Power Management Control ECU)

Connect the cable to the negative (-) battery terminal.

Note

When disconnecting the cable, some systems need to be initialized after the cable is reconnected Click here.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
H72-12 (GND) - Body ground	Always	Below 1 Ω

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

Standard Voltage

Tester Connection	Condition	Specified Condition
H72-8 (AM21) - Body ground	Always	11 to 14 V
H72-2 (IG2) - Body ground	Ignition switch ON	11 to 14 V

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

REPLACE POWER MANAGEMENT CONTROL ECU Click here

REPAIR OR REPLACE HARNESS OR CONNECTOR