How to Proceed With Troubleshooting
CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: HOW TO PROCEED WITH TROUBLESHOOTING
NOTICE:
* Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
* If the CAN communication system is malfunctioning, check the contact pressure of the terminals in connectors as insufficient terminal contact pressure may be the cause.
* DTCs for the CAN communication system are as follows:
U0073, U0100, U0101, U0105, U0121, U0123, U0124, U0126, U0129 and U1110.
1. INSPECT BATTERY VOLTAGE
Standard voltage:
11 to 14 V
HINT
If the voltage is below 11 V, recharge or replace the battery before proceeding to the next step.
NEXT -- Continue to next step.
2. CHECK ENGINE SWITCH OPERATION
(a) Check that the engine switch can be turned on (IG) (vehicle power source system can change to on (IG)).
(b) If the engine switch cannot be turned on (IG), repair this malfunction first.
2GR-FSE: Problem Symptoms Table
4GR-FSE: Problem Symptoms Table
HINT
Even if the engine switch cannot be turned on (IG) (when the vehicle power source system cannot change to on (IG), the data of some ECUs can be checked even with the engine switch off. These ECUs can be checked by connecting the Techstream to the vehicle and turning a door courtesy switch on and off repeatedly to start communication (the on/off operation interval should be less than 1.5 seconds).
2GR-FSE: Power Source Mode Does Not Change To ON (IG and ACC)
4GR-FSE: Power Source Mode Does Not Change To ON (IG and ACC)
NEXT -- Continue to next step.
3. CHECK TECHSTREAM OPERATION
HINT
Read the Techstream operators manual before use General Information.
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Check that the Techstream and ECUs can communicate with the engine switch on (IG).
HINT
* If communication is impossible, the Techstream screen will indicate an error.
* If communication between the Techstream and ECUs is impossible, either the Techstream or vehicle has a malfunction.
* When communication between the Techstream and ECUs is impossible, but communication is normal when the Techstream is connected to another vehicle, the vehicle has the malfunction. Inspect the diagnosis data link line, CANH, CANL and power source circuits of ECUs (in this case perform steps 6 to 8 first). In addition, check that the BAT terminal of the DLC3 receives a battery voltage of 11 V or more when the engine switch is on (IG).
* If communication between the Techstream and ECUs is still impossible even when the Techstream is connected to another vehicle, the Techstream has a malfunction. Perform the self tests described in the Techstream operators manual. (The Techstream may be malfunctioning or its battery may be discharged.)
NEXT -- Continue to next step.
4. CHECK AND CLEAR DTCS
HINT
* CAN communication DTCs are output when there is an open or short in any of the communication wires. Any problems with the power source of a corresponding ECU or sensor, or problems in the ECU, the sensor itself also cause these DTCs to be output.
* If a CAN communication line connector is disconnected with the engine switch on (IG), the ECUs of the corresponding system and related systems store a DTC.
* If an open in a CAN main bus line, a short between the CAN bus lines (CANH and CANL) or a +B or ground short in the CAN bus occurs, DTCs of almost all ECUs (or sensors) on the CAN bus may be output, or a message indicating a communication error may be displayed on the Techstream screen. In this case, check the resistance of the CAN bus (steps 6 to 8) first.
* If an open occurs in just one of the lines of a CAN branch, DTCs which are not related to malfunctioning parts may be output (DTCs may be displayed randomly), or a message indicating a communication error may be displayed.
(a) Check for DTCs and freeze frame date using the Techstream and record them.
(b) Clear the DTCs using the Techstream.
HINT
If DTCs cannot be cleared, perform the following procedure.
(c) Turn the engine switch off and wait at least 15 seconds.
(d) Turn the engine switch on (IG) again.
(e) Clear the DTCs using the Techstream.
NEXT -- Continue to next step.
5. CHECK INSTALLED SYSTEMS (ECUS AND SENSORS) 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 LINE AND CAN BUS CIRCUIT MAIN LINE (CANH - CANL)
NOTICE:
* Turn the engine switch off before measuring the resistances of the CAN main line and the CAN branch line.
* After the engine switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.
* Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the engine switch, any other switches or the doors. If the doors need to be opened in order to check the connectors, open the doors and leave them open.
HINT
Operating the engine switch, any other switches, or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
(a) Turn the engine switch off.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
B -- GO TO "OPEN IN CAN MAIN BUS LINE" Open in CAN Main Bus Line
C -- GO TO "SHORT IN CAN BUS LINES" Short in CAN Bus Lines
A -- Continue to next step.
7. CHECK FOR SHORT TO GND IN CAN BUS (CANH, CANL - CG)
(a) Turn the engine switch off.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- GO TO "SHORT TO GND IN CAN BUS LINE" Short to GND in CAN Bus Line
OK -- Continue to next step.
8. CHECK FOR SHORT TO +B IN CAN BUS (CANH, CANL - BAT)
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- GO TO "SHORT TO +B IN CAN BUS LINE" Short to B+ in CAN Bus Line
OK -- Continue to next step.
9. CHECK FOR OPTIONAL INSTALLED SYSTEMS (ECUS & SENSORS) THAT ADOPT CAN COMMUNICATION
(a) Check which of the following are adopted: navigation system and 4WD.
NEXT -- Continue to next step.
10. CHECK USING TECHSTREAM (CAN BUS CHECK)
(a) Connect the cable to the negative (-) battery terminal.
(b) Turn the engine switch on (IG).
(c) Using the Techstream, select "CAN Bus Check" from "System Select".
Result:
NOTICE:
* The systems (ECUs and sensors) that adopt CAN communication vary depending on the vehicle and optional equipment. Check which systems (ECUs and sensors) are installed on the vehicle.
* Non-installed ECUs or sensors are not displayed. Do not mistake them for being in communication stop mode.
* The systems displayed on the Techstream display are affected by signals output from other ECUs which have an open circuit in either of their CAN branch lines.
B -- GO TO "COMMUNICATION STOP MODE 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.
11. DTC COMBINATION TABLE
(a) Confirm trouble according to the combination of output DTCs regarding the CAN communication system Diagnosis System.
HINT
* Sometimes CAN communication system DTCs are output, but all the ECUs and sensors connected to the CAN communication system are displayed on the Techstream. In this case, previous or history DTCs may indicate the cause of the problem.
* ECUs related to a problem in the CAN bus will store DTCs to indicate communication malfunctions. Communication stop mode in the CAN bus can be determined by comparing the combination of DTCs that have been set. Refer to the DTC combination table for the CAN bus.
NEXT -- Continue to next step.
12. CIRCUIT INSPECTION
NEXT -- Continue to next step.
13. IDENTIFICATION OF PROBLEM
NEXT -- Continue to next step.
14. REPAIR OR REPLACE
NEXT -- Continue to next step.
15. CONFIRMATION TEST
NEXT -- END