As vehicles electronically controlled, various control unit is applied to vehicle and several units are controlled based on the signals from the sensors. Therefore sharing signals of sensors and information is required. To meet this requirement, CAN communication type, which is insensible to external noises and whose communication speed is fast, is applied to power train control.
Sharing signals from RPM, APS, gear shifting, torque reduction in ESP, ABS and various modules, addtive control is performed.
If there is no message from TCU to ECM through external CAN line over 500 ms, PCU sets DTC U0101.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● CAN communication status check | ● Poor connection ● PCM |
Enable Conditions | ● TCU is not coming via internal CAN | |
Threshold Value | ● No message time from TCU via external CAN > 500ms | |
Diagnostic Time | ● Continuous | |
MIL ON Condition | ● 5 sec |
Connect scantool to Data Link Connector(DLC).
Warm up the engine to normal operating temperature.
Monitor the "CAN" parameters on the scantool.
Check "Transaxle type, Torque control request, etc" at the ECU service data mode.
Check "TPS, RPM, IDLE STATE, etc" at the TCU service data mode.
Are the parameters displayed correctly?
▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or wasrepaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poorconnection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of vehicle Repair" procedure..
▶ Substitute with a known-good ECM and check for proper operation. If the problem is corrected, replace ECM and then go to "Verification of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.
Press F4(DTAL) and confirm that "DTC Readiness Flag" indicates "Complete".
If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
Read "DTC Status" parameter.
Is parameter displayed "History(Not Present) fault"?
▶ System performing to specification at this time. Clear the DTC.
▶ Go to the applicable troubleshooting procedure.