DTC P1603: TCM Trouble Code Detected
Wiring Diagram
1. ECM 2. TCM (A/T vehicle)
DTC Detecting Condition
When ECM receives a trouble code from TCM, which indicates that some problem occurred in sensor circuits and its calculated values used for operations such as idle speed control, engine power control, and so on by TCM, ECM sets DTC P1603. (TCM outputs the trouble code to ECM when TCM can not compute the engine control signal due to malfunctions of sensor circuits used for gear shift control.)
DTC Troubleshooting
Step Action YES NO
Was “Engine and Emission Control System Check” performed?
Go to Step 2.
DTC check
1) Check DTC of TCM referring to DTC Check .
Is there any DTC(s)?
Go to applicable DTC diag. flow.
Substitute a known-good ECM and recheck.
Upon completion of inspection and repair work, perform “DTC Confirmation Procedure” and confirm that the trouble has been corrected.