U0101

DTC U0101 CAN COMMUNICATION MALFUNCTION (ECM/PCM - TCM)

Component Location:

GENERAL DESCRIPTION
A communication line exists between the Engine Control Module (ECM) and the Transaxle Control Module(TCM). The communication is through a Control Area Network(CAN). Without CAN communication, an independent pin and wiring is needed to receive a sensor information from a ECM. The more information to be communicated, the more wirings is required. In case of CAN communication type, all the information need to be communicated among control modules such as ECM and TCM use CAN lines.

DTC DESCRIPTION
The ECM sets DTC U0101 if ECM detects that communication time via CAN exceeds threshold value






MONITOR DTC STATUS
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Press F4 (DTAL) to select DTC information from the DTCs menu.
3. Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.




4. Read "DTC Status" parameter.
5. Is parameter displayed "History (Not Present) fault"?

NOTE:
1. History (Not Present) fault: DTC occurred but has been cleared.
2. Present fault: DTC is occurring at present time.

YES - Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary.

NO - Go to "W/Hamess Inspection" procedure

TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?

YES - Repair as necessary and go to "Verification of Vehicle Repair" procedure

NO - Using a scan tool, check ECM software version and upgrade as necessary. If version is the newest one, go to "Verification of Vehicle Repair" procedure

VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode
2. 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.
3. Read "DTC Status" parameter
4. Is parameter displayed "History (Not Present) fault"?

YES - System performing to specification at this time. Clear the DTC

NO - Go to the applicable troubleshooting procedure.