Diagnostic Instructions
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 P062F: Transmission Control Module (TCM) Long Term Memory Performance
Circuit/System Description
This is an internal fault detection of the TCM. This fault is handled inside the TCM and no external circuits are involved.
Conditions for Running the DTC
| • | The TCM runs the program to detect an internal condition at key ON. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range. |
| • | Ignition voltage is between 8.0 and 18.0 volts - DTC P062F only. |
Conditions for Setting the DTC
P0601
The read only memory (ROM) test has failed 5 or more times.
P0602
The TCM has been unable to detected the start program.
P0603
The TCM has detected a memory checksum error.
P0604
The TCM random access memory (RAM) test has failed 5 or more times.
P062F
P062F The TCM has detected a non-volatile memory error during power-down.
Action Taken When the DTC Sets
P0601, P0603, P0604, and P062F
| • | DTC P0601, P0603, P0604, and P062F are type A DTCs. |
| • | The TCM commands maximum line pressure. |
| • | The TCM forces the torque converter clutch (TCC) OFF. |
| • | The TCM inhibits TCC engagement. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM commands a soft landing to 2nd gear. |
P0602
| • | DTC P0602 is a type A DTCs. |
| • | The TCM commands maximum line pressure. |
| • | The TCM forces the torque converter clutch (TCC) OFF. |
| • | The TCM inhibits TCC engagement. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM commands an immediate landing to 2nd gear. |
Conditions for Clearing the DTC
DTC P0601, P0602, P0603, P0604, and P062F are type A DTCs.
Diagnostic Aids
| • | DTC P0601 detects a corruption of the EPROM/Flash memory. |
| • | DTC P0602 detects a non-programmed Transmission Control Module. |
| • | DTC P0603 detects the wrong copy of Non-volatile memory in RAM. |
| • | DTC P0604 detects a Random Access Memory (RAM) read/write failure. |
| • | DTC P062F detects a Non-Volatile Memory write error at key-down. |
| • | 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
Description and Operation Reference
Transmission General Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine running. Let the engine run for at least 1 minute.
- Ignition OFF for at least 30 seconds to allow for the complete shutdown of the TCM.
- Ignition ON, verify that DTC P0602 is not set.
| ⇒ | If DTC P0602 is set, reprogram the TCM. If the DTC resets, replace the TCM. |
- Observe the DTC information with a scan tool. If DTC P0601, P0603, P0604, or P062F are set, replace the TCM.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for TCM replacement, setup, and programming
