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 prevent airbag and seat belt pretensioner activation.
NOTICE:
* DTCs for the CAN communication system are as follows: U0073, U0100, U0101, U0122, U0123, U0124, U0126, U0127, U0128, U0129, U0130, U0131, U0132, U0140, U0141, U0142, U0146, U0151, U0155, U0164, U0182, U0198, U0199, U0200, U0201, U0202, U0208, U0209, U0210, U0230, U0235, U0243, U0327, U1000, U1002, U1004, U1005, U1100, U1101, U1102, U1104, U1105, U1106, U1110, U1111, U1112, U1113, U1114, U1115, U1119, U1120, U1121, B2427, B2621, and B2624
* 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 engine switch, any switches or doors. If doors need to be opened in order to check connectors, open the doors and leave them open.
* w/ Navigation System (for HDD):
After the engine switch is turned off, the display and navigation module display (HDD navigation system) records various types of memory and settings. As a result, after turning the engine switch off, be sure to wait for the time specified in the table before disconnecting the cable from the negative (-) battery terminal.
Waiting Time before Disconnecting Cable from Negative (-) Battery Terminal
* When disconnecting the cable, some systems need to be initialized after the cable is reconnected Repair Instruction - Initialization.
HINT
* Operating the engine 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 FOR DTC (ELECTRIC POWER CONTROL SYSTEM)*
(a) Using the Techstream, check if the electric power control system is functioning normally.
Result
B -- Go to ELECTRIC POWER CONTROL SYSTEM
A -- Continue to next step.
4. CHECK AND CLEAR DTC*
(a) Using the Techstream, perform the ALL DTC check.
NOTICE:
* If a CAN communication malfunction code that informs that an ECU or sensor has a power malfunction or interior malfunction is causing a communication stop, the problem may not be in the communication line. There is a high possibility that the ECU or sensor has a signal transmission failure. Therefore, first troubleshoot any DTCs related to the ECU or sensor.
* When CAN communication related connectors are disconnected with the engine switch on (IG or ACC), the ECU related to the connector and ECUs of related systems will store a CAN communication DTC.
NEXT -- Continue to next step.
5. 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.
6. 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.
NOTICE:
When disconnecting the cable, some systems need to be initialized after the cable is reconnected Repair Instruction - Initialization.
(b) Measure the resistance of the DLC3.
Standard resistance:
B -- GO TO CAN MAIN WIRE FOR DISCONNECTION
C -- GO TO CHECK CAN BUS LINES FOR SHORT CIRCUIT
A -- Continue to next step.
7. CHECK V BUS CIRCUIT +B (CANH, CANL - BAT)
(a) Measure the resistance of the DLC3.
Standard resistance:
NG -- GO TO CHECK CAN BUS LINE FOR SHORT TO +B
OK -- Continue to next step.
8. CHECK V BUS CIRCUIT GND (CANH, CANL - CG)
(a) Measure the resistance of the DLC3.
Standard resistance:
NG -- GO TO CHECK CAN BUS LINE FOR SHORT TO GND
OK -- Continue to next step.
9. CHECK ECUS CONNECTED TO CAN BUS (USING TECHSTREAM)*
(a) Select "CAN Bus Check" from the "System Select".
(b) Wait 1 minute and then check the display of the connected ECUs and sensors.
NOTICE:
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.)
* The main body ECU checks for proper ECU communication for ECUs that are connected to the CAN MS bus circuit, and the results are displayed on the Techstream.
* The driving support ECU checks for proper ECU communication for ECUs that are connected to the parking assist bus, and the results are displayed on the Techstream.
* The gateway ECU built into the main body ECU may be malfunctioning if both of the following occurs: 1) all ECUs connected to the MS bus are not displayed on the Techstream; and 2) DTC U1002 is not output.
* The gateway ECU built into the driving support ECU may be malfunctioning if both of the following occurs: 1) all ECUs connected to the parking assist bus are not displayed on the Techstream; and 2) DTC U1002 is not output.
* The ECM checks for proper ECU communication for ECUs that are connected to the braking and driving bus, and the results are displayed on the Techstream.
* The gateway ECU built into the ECM may be malfunctioning if both of the following occurs: 1) all ECUs connected to the braking and driving bus are not displayed on the Techstream; and 2) DTC U1004 is not output.
* The skid control ECU checks for proper ECU communication for ECUs that are connected to the steering bus, and the results are displayed on the Techstream.
* The gateway ECU built into the skid control ECU may be malfunctioning if both of the following occurs: 1) all ECUs connected to the steering bus are not displayed on the Techstream; and 2) DTC U1005 is not output.
* If communication stops between an ECU and the main body ECU, ECM, skid control ECU or driving support ECU for 10 seconds or more, the ECU disappears from the Techstream display.
* For communication stop mode of ECUs connected to the CAN MS bus, parking assist bus, steering bus, or braking and driving bus, refer to the DTC flowchart of the respective communication stop.
B -- GO TO DTC U1002 FLOWCHART
C -- GO TO MAIN BODY ECU COMMUNICATION STOP MODE FLOWCHART
D -- GO TO DTC U1002 (Parking Assist Bus) FLOWCHART
E -- GO TO DTC U1101 FLOWCHART
F -- GO TO DTC U1004 FLOWCHART
G -- GO TO ECM COMMUNICATION STOP MODE FLOWCHART
H -- GO TO DTC U1005 FLOWCHART
I -- GO TO SKID CONTROL ECU COMMUNICATION STOP MODE FLOWCHART
J -- GO TO PROBLEM SYMPTOMS TABLE
K -- GO TO OPEN IN ONE SIDE OF CAN BRANCH WIRE FLOWCHART
A -- Continue to next step.
10. CHECK COMMUNICATION MALFUNCTION DTC (PAST DTC CHECK)*
(a) Select "CAN Bus Check" from the "System Select".
(b) Write down all of the DTCs stored in each ECU.
HINT
* If there are communication malfunction DTCs stored but the Techstream's "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.
* For MS bus malfunctions, DTCs are output based on the detection of communication stop malfunctions and network malfunctions of ECUs that are connected by the main body ECU.
* For braking and driving bus malfunctions, DTCs are output based on the detection of communication stop malfunctions and network malfunctions of ECUs that are connected by the ECM.
* For steering bus malfunctions, DTCs are output based on the detection of communication stop malfunctions and network malfunctions of ECUs that are connected by the skid control ECU.
* For parking assist bus malfunctions, DTCs are output based on the detection of communication stop malfunctions and network malfunctions of ECUs that are connected by the driving support ECU.
B -- GO TO DTC U1002 FLOWCHART
C -- GO TO PROBLEM SYMPTOMS TABLE
D -- GO TO DTC U1004 FLOWCHART
E -- GO TO PROBLEM SYMPTOMS TABLE
F -- GO TO DTC U1005 FLOWCHART
G -- GO TO PROBLEM SYMPTOMS TABLE
H -- GO TO U1002 (Parking Assist Bus) FLOWCHART
I -- GO TO DIAGNOSIS SYSTEM
A -- Continue to next step.
11. 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.
12. 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 output as a result of the malfunction simulation test. Then determine the malfunctioning area.
NEXT -- Continue to next step.
13. ADJUST, REPAIR AND REPLACE
NEXT -- Continue to next step.
14. CONFIRMATION TEST
NEXT -- END