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How to Proceed With Troubleshooting





CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: HOW TO PROCEED WITH TROUBLESHOOTING

Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and the branch wire.

CAUTION:
Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

NOTICE:
* DTCs for the CAN communication system are as follows: U0073, U0100, U0123, U0124, U0126, U0129 and U0151.
* Refer to the troubleshooting procedures of each system if DTCs regarding the CAN communication system are not output.
* Before measuring the resistance, leave the vehicle for at least 1 minute and do not operate the ignition switch, any switches or 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.
* *: Use the Techstream.

1. VEHICLE BROUGHT TO WORKSHOP

NEXT -- Continue to next step.

2. INSPECT BATTERY VOLTAGE

Standard voltage:

11 to 14 V

If the voltage is below 11 V, recharge or replace the battery before proceeding.

NEXT -- Continue to next step.

3. CHECK AND CLEAR DTC*

(a) Using the Techstream, perform the Health Check (all DTCs check).

NOTICE:
* If there is a CAN communication trouble code that indicates that an ECU or sensor has a power malfunction or interior malfunction which is causing a communication stop, the problem may not be in the communication line.
* When CAN communication related connectors are disconnected with the ignition switch ON or ACC, the ECU related to the connector and ECUs of related systems will store a CAN communication DTC.

NEXT -- Continue to next step.

4. CHECK INSTALLED SYSTEMS (ECU AND SENSOR) THAT USE CAN COMMUNICATION

(a) Based on the vehicle equipment and specifications, confirm the systems that use CAN communication Diagnosis System.

NEXT -- Continue to next step.

5. CHECK DLC3 BRANCH WIRE AND V BUS CIRCUIT MAIN WIRE (CANH - CANL)

(a) Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and the branch wire.

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





Standard Resistance:





Text in Illustration





B -- Go to OPEN IN CAN MAIN BUS LINE Open in CAN Main Bus Line

C -- Go to CHECK CAN BUS LINES FOR SHORT CIRCUIT
A -- Continue to next step.

6. CHECK V BUS CIRCUIT +B (CANH, CANL - BAT)

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





Standard Resistance:





Text in Illustration





Result





B -- Go to CHECK CAN BUS LINE FOR SHORT TO +B
A -- Continue to next step.

7. CHECK V BUS CIRCUIT GND (CANH, CANL - CG)

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





Standard Resistance:





Text in Illustration





Result





B -- Go to CHECK CAN BUS LINE FOR SHORT TO GND
A -- Continue to next step.

8. CHECK ECUS CONNECTED TO CAN BUS*

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

(b) Select "CAN Bus Check" from "System Select".

(c) Wait 1 minute and then check the display of the connected ECUs and sensors.

Result





NOTICE:
The ECUs and sensors that are not present will not be displayed. Be careful not to mistake them for communication stop malfunctions.

HINT
If the display of an ECU is intermittent during the check, one side of an ECU or sensor branch wire is open (The signal of the ECU is treated as noise, which affects the response and display of the Techstream).

B -- Go to PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

C -- Go to OPEN IN ONE SIDE OF CAN BRANCH LINE Open in One Side of CAN Branch Line
A -- Continue to next step.

9. CHECK COMMUNICATION MALFUNCTION DTC (PAST DTC CHECK)*

(a) Select "CAN Bus Check" from "System Select".

(b) Write down all of the DTCs stored in each ECU.

HINT
* If there are communication malfunction DTCs stored but the Techstream "CAN Bus Check - Communication Bus Check" screen displays all of the ECUs and sensors connected to the CAN system, the communication malfunction DTCs may be past malfunctions that are no longer present.
* For V bus main wire malfunctions, related ECUs are also detected. Therefore, determine the malfunctioning area based on all of the DTCs that are output.

NEXT -- Continue to next step.

10. CHECK DTC COMBINATION TABLE (V BUS CIRCUIT BRANCH WIRE OPEN PAST MALFUNCTION)

(a) Based on the combination of stored CAN communication system DTCs, determine which ECUs and sensors have a communication stop malfunction Diagnosis System.

NEXT -- Continue to next step.

11. PERFORM MALFUNCTION SIMULATION TEST (V BUS CIRCUIT MAIN WIRE PAST MALFUNCTION)*

(a) Using the Techstream, clear all DTCs.

(b) Perform a malfunction simulation test on all harnesses and connectors related to the V bus circuit main wire.

(c) Check the DTCs that were stored as a result of the malfunction simulation test. Then determine the malfunctioning area.

NEXT -- Continue to next step.

12. ADJUST, REPAIR AND REPLACE

NEXT -- Continue to next step.

13. CONFIRMATION TEST

NEXT -- END
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