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Open in One Side of CAN Branch Line








CAN COMMUNICATION SYSTEM: Open in One Side of CAN Branch Line

Open in One Side of CAN Branch Line

DESCRIPTION

If two or more ECUs and/or sensors do not appear on a Techstream "Communication Bus Check" screen, one side of the CAN branch wire may be open. (one side of the CAN-H [branch wire] / CANL [branch wire] of the ECU and/or sensor is open.)





HINT:
- *1: w/ ABS
- *2: w/ Air conditioning or PTC heater

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
- Turn the ignition switch OFF before measuring the resistances of the CAN main wire and the CAN branch wire.
- After the ignition switch is turned off, check that the key reminder warning system and light reminder warning system are not in operation.
- Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches or the doors. If doors need to be opened in order to check connectors, open the doors and leave them open.
HINT: Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
HINT:
- Perform the following inspection for the ECUs (sensors) which are not displayed on the intelligent tester. If malfunction cannot be identified, then perform the following inspections for the ECUs (sensors) connected to CAN communication.
- Do not remove the power steering ECU and ECM, as they are the end parts of the circuit. If removed, CAN communication will not be possible.
- The open circuit confirmation of the power steering ECU, ECM and main wire is performed in the CHECK CAN BUS LINE procedure of HOW TO PROCEED WITH TROUBLESHOOTING. This inspection only has procedures for checking for an open circuit on one side of the CAN branch wire.

PROCEDURE

1. CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (BRAKE ACTUATOR (SKID CONTROL ECU))
NOTE: For vehicles without ABS, go to step 3.





(a) Disconnect the A15 brake actuator (skid control ECU) connector.
(b) Select "BUS CHECK" on the intelligent tester via the CAN VIM Diagnosis System.
Result:






B -- CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (AIR CONDITIONING AMPLIFIER)
A -- Continue to next step.
2. CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (BRAKE ACTUATOR (SKID CONTROL ECU) BRANCH WIRE)





(a) Measure the resistance.
HINT: The resistance must be measured after the A15 brake actuator (skid control ECU) connector is disconnected.

Standard resistance:






NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO BRAKE ACTUATOR (SKID CONTROL ECU) (CAN-H, CAN-L)
OK -- REPLACE BRAKE ACTUATOR (SKID CONTROL ECU)
3. CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (AIR CONDITIONING AMPLIFIER)
NOTE: For vehicles without air conditioning or PTC heater, go to step 5.





(a) Disconnect the E8 air conditioning amplifier connector.
(b) Select "CAN Bus Check" on the Techstream Diagnosis System.
Result:






B -- CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (CENTER AIRBAG SENSOR ASSEMBLY)
A -- Continue to next step.
4. CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (AIR CONDITIONING AMPLIFIER BRANCH WIRE)





(a) Measure the resistance.
HINT: The resistance must be measured after the E8 air conditioning amplifier connector is disconnected.

Standard resistance:






NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO AIR CONDITIONING AMPLIFIER (CAN-H, CAN-L)
OK -- REPLACE AIR CONDITIONING AMPLIFIER
5. CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (CENTER AIRBAG SENSOR ASSEMBLY)





(a) Disconnect the D16 center airbag sensor assembly connector.
(b) Select "CAN Bus Check" on the Techstream Diagnosis System.
Result:






B -- CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (MAIN BODY ECU)
A -- Continue to next step.
6. CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (CENTER AIRBAG SENSOR ASSEMBLY BRANCH WIRE)





(a) Measure the resistance.
HINT: The resistance must be measured after the D16 center airbag sensor assembly connector is disconnected.

Standard resistance:






NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO CENTER AIRBAG SENSOR ASSEMBLY (CAN-H, CAN-L)
OK -- REPLACE CENTER AIRBAG SENSOR ASSEMBLY
7. CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (MAIN BODY ECU)





(a) Disconnect the D33 main body ECU connector.
(b) Select "CAN Bus Check" on the Techstream Diagnosis System.
Result:






B -- CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (COMBINATION METER ECU)
A -- Continue to next step.
8. CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (MAIN BODY ECU BRANCH WIRE)





(a) Measure the resistance.
HINT: The resistance must be measured after the D33 main body ECU connector is disconnected.

Standard resistance:






NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO MAIN BODY ECU (CAN-H, CAN-L)
OK -- REPLACE MAIN BODY ECU
9. CHECK OPEN IN ONE SIDE OF CAN BRANCH WIRE (COMBINATION METER ECU)
(a) Disconnect the D1 combination meter ECU connector.





(b) Measure the resistance.
Standard resistance:






NG -- REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO COMBINATION METER ECU (CAN-H, CAN-L)
OK -- REPLACE COMBINATION METER ECU
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