P1603

DTC P1603 CAN COMMUNICATION BUS OFF





COMPONENT LOCATION

GENERAL DESCRIPTION
The TCM can either receive data from the Engine Control Module or ABS control module, or it can send data to the ECM and ABSCM by using CAN communication. The CAN communication is one of the vehicle communications method, which is now widely used to transfer the vehicle data.

DTC DESCRIPTION
When the TCM cannot read the data from the ECM through the CAN-BUS line, the TCM sets this code.
CAN-BUS circuit malfunctioning or ECM can be a possible cause of this DTC.





DTC DETECTING CONDITION

MONITOR SCANTOOL DATA
1. Connect scan tool to data link connector (DLC).
2. Engine "ON".
3. Monitor the "CAN COMMUNICATION SERVICE DATA (ENGINE RPM, VEHICLE SPEED SENSOR, THROTTLE P. SENSOR)" parameters on the scan tool.





4. Compare it with reference data as below.
5. Does "CAN BUS LINE DATA" follow the reference data?
YES Fault is intermittent caused by poor contact in the sensor's and/or TCM's connector or was repaired and TCM memory was not cleared. And go to Verification of Vehicle Repair procedure.
NO Go to "Terminal & Connector Inspection" procedure.

TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness 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 Fault is intermittent caused by poor contact in the sensor's and/or TCM's connector or was repaired and TCM memory was not cleared. And go to Verification of Vehicle Repair procedure.
NO Go to "Signal circuit inspection" procedure.

SIGNAL CIRCUIT INSPECTION
1. Ignition "ON" & Engine "OFF".
2. Disconnect the "TCM" connector.





3. Measure resistance between terminal "3" and "4" of the "TCM" harness connector.
Specification: approximately 60 ohms
4. Is measured resistance within specifications?
YES Substitute with a known-good TCM and check for proper operation. If the problem is corrected, replace TCM as necessary and then go to "Verification of Vehicle Repair" procedure.
NO Check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration or damage of ECM, and then Repair or replace Resistance for CAN communication as necessary and go to "Verification 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. Using a scan tool, Clear DTC.
3. Operate the vehicle within DTC Enable conditions in General information.
4. Are any DTCs present?
YES Go to the applicable troubleshooting procedure.
NO System performing to specification at this time.