Checking CAN Communication Circuit

WARNING: This page is about a different car, the 2018 Subaru BRZ. However, it is still accessible from the selected car via links, so may be relevant.

Inspection steps

CAUTION:

Before measuring the resistance of CAN bus, turn the ignition OFF and leave the vehicle as is for at least one minute without operating keys, switches, and doors. Disconnect the battery and wait for another one minute or more.
When a connector is not fully connected, it may case CAN communication failure. To avoid such failure, make sure to perform contact pressure test.

Bring in the car

Use the tester to measure the resistance between terminals.

STANDARD VALUE SPECIFICATION - RESISTANCE

Inspection terminals	Inspection conditions	Standard value
D10-6 - chassis ground	Always	10Ω or more
D10-14 - chassis ground	Always	10Ω or more

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NG: Check for ground short. (Refer to CHECK FOR SHORT TO GROUND )

OK: Go to next step

Checking from data link connector

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Use the tester to measure the voltage between terminals.

STANDARD VALUE SPECIFICATION - VOLTAGE

Inspection terminals	Inspection conditions	Standard value
D10-6 - chassis ground	Always	Less than 5 V
D10-14 - chassis ground	Always	Less than 5 V

NG: Check for short circuit in the battery (Refer to CHECK FOR SHORT TO BATTERY )

OK: Go to next step

Checking from data link connector

Use the tester to measure the resistance between terminals.

STANDARD VALUE SPECIFICATION - RESISTANCE

Inspection terminals	Inspection conditions	Standard value
D10-6 - D10-14	Always	57 to 63 0

Courtesy of SUBARU OF AMERICA, INC.

RESULT DESCRIPTION - CRITERIA

Result	Go to
OK (57 to 63 0)	A
NG: (exceeding 63 0)	B
NG: (less than 57 0)	C

A: A sub-line may be open. Perform the inspection for the resistance between the sub-lines relevant to the detected DTC. (Refer to 2. list below)

B: Perform the inspection for the resistance of more than 63 Ω. (Refer to EXCEEDING 63 Ω )

C: Perform the inspection for the resistance of Less than 57 Ω. (Refer to LESS THAN 57 Ω )

List

Item	Contents	Note
Check for short to ground	Refer to "CHECK FOR SHORT TO GROUND ".	Shorted to ground in the communication circuit or control module.
Check for short to battery	Refer to "CHECK FOR SHORT TO BATTERY ".	Shorted to battery power supply system in the communication circuit or control module.
Less than 57 0	Refer to the inspection for the resistance of less than 57 0. (Refer to LESS THAN 57 Ω )	CAN-H and CAN-L may be shorted on CAN communication circuit, where the resistance is lower than combined resistance of the terminal resistor.
Exceeding 63 Ω	Refer to the inspection for the resistance of more than 63 Ω. (Refer to EXCEEDING 63 Ω )	CAN communication circuit may be open on CAN communication circuit, where the resistance is higher than combined resistance of the terminal resistor.
Sub-lines 57-63 Ω (Engine control computer system)	Refer to the inspection for the sub-lines 57-63 Ω (Engine control computer system). (Refer to SUB-LINES 57-63 Ω (ENGINE CONTROL COMPUTER SYSTEM) )	The inspection is applied in case of missing or invalid data for the engine control computer.
Sub-lines 57-63 Ω (Brake actuator ASSY system)	Refer to the inspection for the sub-lines 57-63 Ω (Brake actuator ASSY system). (Refer to SUB-LINES 57-63 Ω (BRAKE ACTUATOR SYSTEM) )	The inspection is applied in case of missing or invalid data for the brake actuator ASSY.
Sub-lines 57-63 Ω (Transmission control computer ASSY system)	Refer to the inspection for the sub-lines 57-63 Ω (Transmission control computer ASSY system). (Refer to SUB-LINES 57-63 Ω (TRANSMISSION CONTROL COMPUTER ASSY SYSTEM) )	The inspection is applied in case of missing or invalid data for the transmission control computer ASSY.
Sub-lines 57-63 Ω (Body integrated unit system)	Refer to the inspection for the sub-lines 57-63 Ω (Body integrated unit system). (Refer to SUB-LINES 57-63 Ω (BODY INTEGRATED UNIT SYSTEM) )	The inspection is applied in case of missing or invalid data for the body integrated unit.
Sub-lines 57-63 Ω (Spiral cable SUB-ASSY system)	Refer to the inspection for the sub-lines 57-63 Ω (Spiral cable SUB-ASSY system). (Refer to SUB-LINES 57-63 Ω (SPIRAL CABLE SUB-ASSY SYSTEM) )	The inspection is applied in case of missing or invalid data for the spiral cable SUB-ASSY.
Sub-lines 57-63 Ω (Air conditioner amplifier ASSY system)	Refer to the inspection for the sub-lines 57-63 Ω (A/C control panel system). (Refer to SUB-LINES 57-63 Ω (AIR CONDITIONER CONTROL PANEL SYSTEM) )	The inspection is applied in case of missing or invalid data for A/C.
Sub-lines 57-63 Ω (Electric power steering computer ASSY system)	Refer to the inspection for the sub-lines 57-63 Ω (Electric power steering computer ASSY system). (Refer to SUB-LINES 57-63 Ω (ELECTRIC POWER STEERING SYSTEM) )	The inspection is applied in case of missing or invalid data for the electric power steering.
Sub-lines 57-63 Ω (Combination meter ASSY system)	Refer to the inspection for the sub-lines 57-63 Ω (Combination meter ASSY system). (Refer to SUB-LINES 57-63 Ω (COMBINATION METER ASSY SYSTEM) )	The inspection is applied in case of missing or invalid data for the meter.
Sub-lines 57-63 Ω (Airbag system)	Refer to the inspection for the sub-lines 57-63 Ω (A/B Control Module system). (Refer to SUB-LINES 57-63 Ω (AIRBAG SYSTEM) )	The inspection is applied in case of missing or invalid data for the airbag.
Sub-lines 57-63 Ω (Keyless access system)	Refer to the inspection for the sub-lines 57-63 Ω (Keyless access system). (Refer to SUB-LINES 57-63 Ω (KEYLESS ACCESS SYSTEM) DESCRIPTION OF FUNCTIONS )	The inspection is applied in case of missing or invalid data for the collation ECM (Smart key computer ASSY).