CAN Communication Circuit Check: Inspection: Wiring Diagram

WARNING: This page is about a different car, the 2016 Subaru Outback and 2016 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (Ground Short Inspection) - Wiring Diagram (Main-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: Main wiring harness or related lines may be shorted to ground, or shorted to ground in one of the control modules.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Using the tester, measure the resistance between terminals. Connector & terminal (B40) No. 6 - Chassis ground: (B40) No. 14 - Chassis ground:	Is the resistance 10 Ω or less?	Go to step 2 .	Currently, it is normal.
2 CHECK CONTROL MODULE. With the tester connected, disconnect control module. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (B40) No. 6 - Chassis ground: (B40) No. 14 - Chassis ground:	Did the resistance change to 10 Ω or more?	Replace the control module whose resistance has changed. When the value changed at disconnecting the body integrated unit, Go to step 3 .	Repair or replace the short circuit of the main wiring harness and related lines between body integrated unit and ECM.
3 CHECK BETWEEN MAIN WIRING HARNESSES. Using the tester, measure the resistance between terminals. Connector & terminal (i171) No. 22 - Chassis ground: (i171) No. 2 - Chassis ground:	Is the resistance 10 Ω or less?	Repair or replace the short circuit of the main wiring harness and related lines between ECM and body integrated unit.	Replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. >

BODY-CAN

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (Ground Short Inspection) - Wiring Diagram (Body-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: Main wiring harness or related lines may be shorted to ground, or shorted to ground in one of the control modules.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Using the tester, measure the resistance between terminals. Connector & terminal (i188) No. 5 - Chassis ground: (i188) No. 6 - Chassis ground:	Is the resistance 10 Ω or less?	Go to step 2 .	Currently, it is normal.
2 CHECK CONTROL MODULE. With the tester connected, disconnect control module. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (i188) No. 5 - Chassis ground: (i188) No. 6 - Chassis ground:	Did the resistance change to 10 Ω or more?	Replace the control module whose resistance has changed. When the value changed at disconnecting the body integrated unit, Go to step 3 .	Repair or replace the short circuit of the main wiring harness or related lines between body integrated unit and impact sensor.
3 CHECK BETWEEN MAIN WIRING HARNESSES. Using the tester, measure the resistance between terminals. Connector & terminal (B281) No. 31 - Chassis ground: (B281) No. 15 - Chassis ground:	Is the resistance 10 Ω or less?	Repair or replace the short circuit of the main wiring harness and related lines between ECM and body integrated unit.	Replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. >

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (Battery Short Inspection) - Wiring Diagram (Main-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: Main wiring harness or related lines may be shorted to battery circuit, or shorted to battery circuit in one of the control modules.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Turn the ignition switch to ON. Using the tester, measure the voltage between terminals. Connector & terminal (B40) No. 6 - Chassis ground: (B40) No. 14 - Chassis ground:	Is the voltage 5 V or less?	Currently, it is normal.	Go to step 2 .
2 CHECK CONTROL MODULE. With the tester connected, disconnect control module. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (B40) No. 6 - Chassis ground: (B40) No. 14 - Chassis ground:	Did the voltage change to 5 V or less?	Replace the control module whose voltage has changed. When the value changed at disconnecting the body integrated unit, Go to step 3 .	Repair or replace the short circuit of the harness between body integrated unit and ECM.
3 CHECK BETWEEN MAIN WIRING HARNESSES. Using the tester, measure the voltage between terminals. Connector & terminal (i171) No. 22 - Chassis ground: (i171) No. 2 - Chassis ground:	Is the voltage 5 V or less?	Replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. >	Repair or replace the short circuit of the harness between ECM and body integrated unit.

BODY-CAN

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (Battery Short Inspection) - Wiring Diagram (Body-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: Main wiring harness or related lines may be shorted to battery circuit, or shorted to battery circuit in one of the control modules.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Turn the ignition switch to ON. Using the tester, measure the voltage between terminals. Connector & terminal (i188) No. 5 - Chassis ground: (i188) No. 6 - Chassis ground:	Is the voltage 5 V or less?	Currently, it is normal.	Go to step 2 .
2 CHECK CONTROL MODULE. With the tester connected, disconnect control module. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (i188) No. 5 - Chassis ground: (i188) No. 6 - Chassis ground:	Did the voltage change to 5 V or less?	Replace the control module whose voltage has changed. When the value changed at disconnecting the body integrated unit, Go to step 3 .	Repair or replace the short circuit of the harness between body integrated unit and impact sensor.
3 CHECK BETWEEN MAIN WIRING HARNESSES. Using the tester, measure the voltage between terminals. Connector & terminal (B281) No. 31 - Chassis ground: (B281) No. 15 - Chassis ground:	Is the voltage 5 V or less?	Replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. >	Repair or replace the short circuit of the harness between ECM and body integrated unit.

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (53 - 61 Ω) - Wiring Diagram (Main-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: When the measured resistance value is 53 - 61 Ω, main wiring harness or related lines may be shorted to ground, or shorted to power supply line, or related line may be open.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Using the tester, measure the resistance between terminals. Connector & terminal (B40) No. 6 - Chassis ground: (B40) No. 14 - Chassis ground:	Is the resistance 10 Ω or less?	Go to step 2 .	Go to step 3 .
2 CHECK CONTROL MODULE. With the tester connected, disconnect control module. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (B40) No. 6 - Chassis ground: (B40) No. 14 - Chassis ground:	Did the resistance change to 10 Ω or more?	Replace the control module whose resistance has changed. When the value changed at disconnecting the body integrated unit, replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. > Go to step 3 .	Repair or replace the short circuit of the harness between body integrated unit and ECM.
3 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Turn the ignition switch to ON. Using the tester, measure the voltage between terminals. Connector & terminal (B40) No. 6 - Chassis ground: (B40) No. 14 - Chassis ground:	Is the voltage 5 V or less?	CAN communication circuit is normal.	Go to step 4 .
4 CHECK CONTROL MODULE. With the tester connected, disconnect control module. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (B40) No. 6 - Chassis ground: (B40) No. 14 - Chassis ground:	Did the voltage change to 5 V or less?	Replace the control module whose voltage has changed. When the value changed at disconnecting the body integrated unit, replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. > Go to step 5 .	Repair or replace the short circuit of the harness between body integrated unit and ECM.
5 CHECK HARNESS. Using a tester, measure the voltage between terminals and chassis ground. Connector & terminal (i171) No. 22 - Chassis ground: (i171) No. 2 - Chassis ground:	Is the voltage 5 V or less?	CAN communication circuit is normal.	Repair or replace the short circuit of the harness between ECM and body integrated unit.

BODY-CAN

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (53 - 61 Ω) - Wiring Diagram (Body-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: When the measured resistance value is 53 - 61 Ω, main wiring harness or related lines may be shorted to ground, or shorted to power supply line, or related line may be open.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Using the tester, measure the resistance between terminals. Connector & terminal (i188) No. 5 - Chassis ground: (i188) No. 6 - Chassis ground:	Is the resistance 10 Ω or less?	Go to step 2 .	Go to step 3 .
2 CHECK CONTROL MODULE. With the tester connected, disconnect control module. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (i188) No. 5 - Chassis ground: (i188) No. 6 - Chassis ground:	Did the resistance change to 10 Ω or more?	Replace the control module whose resistance has changed. When the value changed at disconnecting the body integrated unit, replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. > Go to step 3 .	Repair or replace the short circuit of the harness between body integrated unit and ECM.
3 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Turn the ignition switch to ON. Using the tester, measure the voltage between terminals. Connector & terminal (i188) No. 5 - Chassis ground: (i188) No. 6 - Chassis ground:	Is the voltage 5 V or less?	CAN communication circuit is normal.	Go to step 4 .
4 CHECK CONTROL MODULE. With the tester connected, disconnect control module. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (i188) No. 5 - Chassis ground: (i188) No. 6 - Chassis ground:	Did the voltage change to 5 V or less?	Replace the control module whose voltage has changed. When the value changed at disconnecting the body integrated unit, replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. > Go to step 5 .	Repair or replace the short circuit of the harness between body integrated unit and ECM.
5 CHECK HARNESS. Using a tester, measure the voltage between terminals and chassis ground. Connector & terminal (B281) No. 31 - Chassis ground: (B281) No. 15 - Chassis ground:	Is the voltage 5 V or less?	CAN communication circuit is normal.	Repair or replace the short circuit of the harness between combination meter and body integrated unit.

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (52 Ω Or Less) - Wiring Diagram (Main-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: When the bus line is measured, combined resistance of the end resistance (120 Ω) in ECM and the end resistance (120 Ω) in body integrated unit can be measured. The combined resistance is approximately 53 - 61 Ω with the stabilizing circuit included. When the measured resistance value is 52 Ω or less, main wiring harness or related lines may be shorted, or combined resistance may have changed because resistance other than end resistance is created on the circuit.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Using the tester, measure the resistance between terminals. Connector & terminal (B40) No. 6 - No. 14:	Is the resistance 10 Ω or less?	Go to step 2 .	Go to step 3 .
2 CHECK MAIN WIRING HARNESS AND RELATED LINES. With a tester connected, disconnect control module connectors in order. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (B40) No. 6 - No. 14:	Is there any control module whose condition has changed from short state?	Replace the control module whose resistance has changed. When the value changed at disconnecting the body integrated unit, replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. > Go to step 3 .	Repair or replace the short circuit of the harness between body integrated unit and ECM.
3 CHECK CONTROL MODULE. Disconnect the connectors of ECM and body integrated unit. Using a tester, measure the resistance between control module terminals. Connector & terminal (B134) No. 24 - (B134) No. 25: (i171) No. 22 - (i171) No. 2:	Is the resistance 114 - 126 Ω?	Go to step 4 .	Replace the control module whose end resistance value is out of the specified range.
4 CHECK HARNESS. Using the tester, check the short circuit of each harness. Connector & terminal (i171) No. 22 - (i171) No. 2:	Is the resistance 1 MΩ or more?	CAN communication circuit is normal.	Go to step 5 .
5 CHECK CONTROL MODULE. With a tester connected, disconnect control modules in order. Connector & terminal (i171) No. 22 - (i171) No. 2:	Are there any control modules whose resistance changed to 1 MΩ or more?	Replace the control module that has changed.	Repair or replace the harness part which has resistance component.

BODY-CAN

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (52 Ω Or Less) - Wiring Diagram (Body-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: When the bus line is measured, combined resistance of the end resistance (120 Ω) in body integrated unit and the end resistance (120 Ω) in combination meter can be measured. The combined resistance is approximately 53 - 61 Ω with the stabilizing circuit included. When the measured resistance value is 52 Ω or less, main wiring harness or related lines may be shorted, or combined resistance may have changed because resistance other than end resistance is created on the circuit.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK BETWEEN RELATED LINES AND MAIN WIRING HARNESS. Using the tester, measure the resistance between terminals. Connector & terminal (i188) No. 5 - (i188) No. 6:	Is the resistance 10 Ω or less?	Go to step 2 .	Go to step 3 .
2 CHECK MAIN WIRING HARNESS AND RELATED LINES. With a tester connected, disconnect control module connectors in order. NOTE: Disconnect the body integrated unit at the end. Connector & terminal (i188) No. 5 - (i188) No. 6:	Is there any control module whose condition has changed from short state?	Replace the control module whose resistance has changed. When the value changed at disconnecting the body integrated unit, replace the body integrated unit. < Ref. to REMOVAL , Body Integrated Unit. > Go to step 3 .	Repair or replace the short circuit of the harness between body integrated unit and ECM.
3 CHECK CONTROL MODULE. Disconnect the connectors of the body integrated unit and combination meter. Using a tester, measure the resistance between control module terminals. Connector & terminal (B281) No. 15 - (B281) No. 31: (i10) No. 6 - (i10) No. 7:	Is the resistance 114 - 126 Ω?	Go to step 4 .	Replace the control module whose end resistance value is out of the specified range.
4 CHECK HARNESS. Using the tester, check the short circuit of each harness. Connector & terminal (i10) No. 6 - (i10) No. 7:	Is the resistance 1 MΩ or more?	CAN communication circuit is normal.	Go to step 5 .
5 CHECK CONTROL MODULE. With a tester connected, disconnect control modules in order. Connector & terminal (i10) No. 6 - (i10) No. 7:	Are there any control modules whose resistance changed to 1 MΩ or more?	Replace the control module that has changed.	Repair or replace the harness part which has resistance component.

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (62 Ω Or More) - Wiring Diagram (Main-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: When the CAN communication circuit is measured, combined resistance of the end resistance (120 Ω) in ECM and the end resistance (120 Ω) in body integrated unit can be measured. The combined resistance is approximately 53 - 61 Ω with the stabilizing circuit included. When the measured resistance value is 62 Ω or more, either one of the end resistances, or stabilizing circuit, or main wiring harness may have malfunction such as open circuit.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK CONTROL MODULE. Disconnect the connectors of ECM and body integrated unit. Using a tester, measure the resistance between control module terminals. Connector & terminal (B134) No. 24 - (B134) No. 25: (i171) No. 2 - (i171) No. 22:	Is the resistance 114 - 126 Ω?	Go to step 2 .	Replace the control module whose value is out of the specification.
2 CHECK HARNESS. Using a tester, check continuity between terminals. Connector & terminal (B40) No. 6 - (B134) No. 25: (B40) No. 14 - (B134) No. 24: (B40) No. 6 - (i171) No. 22: (B40) No. 14 - (i171) No. 2:	Is there continuity?	Go to step 3 .	Repair or replace the open circuit of harness.
3 CHECK HARNESS. Disconnect the combination meter connector. Using a tester, check continuity between terminals. Connector & terminal (B281) No. 31 - (i10) No. 6: (B281) No. 15 - (i10) No. 7:	Is there continuity?	It is possible that temporary poor communication occurs.	Repair or replace the open circuit of harness.

BODY-CAN

NOTE: For the coupling connector, refer to "WIRING SYSTEM".

CAN communication system < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >

Fig 1: CAN Communication (62 Ω Or More) - Wiring Diagram (Body-CAN)

Courtesy of SUBARU OF AMERICA, INC.

NOTE: When the CAN communication circuit is measured, combined resistance of the end resistance (120 Ω) in body integrated unit and the end resistance (120 Ω) in combination meter can be measured. The combined resistance is approximately 53 - 61 Ω with the stabilizing circuit included. When the measured resistance value is 62 Ω or more, either one of the end resistances, or stabilizing circuit, or main wiring harness may have malfunction such as open circuit.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK CONTROL MODULE. Disconnect the connectors of the body integrated unit and combination meter. Using a tester, measure the resistance between control module terminals. Connector & terminal (B281) No. 15 - (B281) No. 31: (i10) No. 6 - (i10) No. 7:	Is the resistance 114 - 126 Ω?	Go to step 2 .	Replace the control module whose value is out of the specification.
2 CHECK HARNESS. Using a tester, check continuity between terminals. Connector & terminal (B40) No. 6 - (B134) No. 25: (B40) No. 14 - (B134) No. 24: (B40) No. 6 - (i171) No. 22: (B40) No. 14 - (i171) No. 2:	Is there continuity?	Go to step 3 .	Repair or replace the open circuit of harness.
3 CHECK HARNESS. Disconnect the combination meter connector. Using a tester, check continuity between terminals. Connector & terminal (B281) No. 31 - (i10) No. 6: (B281) No. 15 - (i10) No. 7:	Is there continuity?	It is possible that temporary poor communication occurs.	Repair or replace the open circuit of harness.