DTC Descriptors
DTC P0601: Transmission Control Module (TCM) Read Only Memory (ROM)DTC P0602: Transmission Control Module (TCM) Not Programmed
DTC P0603: Transmission Control Module (TCM) Long Term Memory Reset
DTC P0604: Transmission Control Module (TCM) Random Access Memory (RAM)
DTC P1621: Transmission Control Module (TCM) Long Term Memory Performance
Diagnostic Fault Information
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit/System Description
This is an internal fault detection of the control solenoid (w/body and TCM) valve assembly. This fault is handled inside the control solenoid (w/body and TCM) valve assembly and no external circuits are involved.
Conditions for Running the DTC
| • | The control solenoid (w/body and TCM) valve assembly runs the program to detect an internal fault when the key is ON or the engine is running. |
| • | Ignition voltage is 8-18 volts. |
Conditions for Setting the DTC
The control solenoid (w/body and TCM) valve assembly has detected an internal malfunction.
Action Taken When the DTC Sets
| • | DTCs P0601, P0602, P0603, P0604, and P1621 are Type A DTCs. |
| • | The TCM shifts to a default gear, shuts down, and turns OFF. |
Conditions for Clearing the DTC
DTCs P0601, P0602, P0603, P0604, and P1621 are Type A DTCs.
Diagnostic Aids
When attempting to set TCM internal DTCs let the engine run for at least 1 minute and then shut the engine off for 30 seconds. Following this procedure will allow for a complete TCM shutdown. Reprogram the TCM and retest the DTC to see if the DTC resets.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
DTC Type Reference
Electrical Information Reference
Circuit/System Verification
- Start the engine.
- Let the engine run for 1 minute, then shut the engine OFF for 30 seconds.
- Retest for DTCs P0601, P0602, P0603, P0604, and P1621.
Circuit/System Testing
Reprogram the TCM and recheck for DTCs.
| ⇒ | If the DTC resets, replace the control solenoid (w/body and TCM) valve assembly. |
Component Testing
Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Perform the Service Fast Learn Adapts .
