For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### 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 control solenoid (w/body and TCM) valve assembly. This fault is carried out 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 between 8.6-18.0 volts - DTC P062F only.

### Conditions for Setting the DTC

#### P0601

The read only memory (ROM) test has failed 5 or more times.

#### P0602

The transmission control module (TCM) has detected no 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

The TCM has detected non-volatile memory is incorrect during power-down.

### Action Taken When the DTC Sets

• | DTCs P0601, P0602, P0603, P0604, and P062F 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 P062F 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 at least 30 seconds. Following this procedure will allow a complete TCM shutdown. Reprogram the TCM and retest the DTC to see if the DTC resets.

### Reference Information

#### Description and Operation

Electronic Component Description

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

### Circuit/System Verification

1. Start the engine.
2. Let the engine run for 1 minute, then shut the engine OFF for at least 30 seconds.
3. Retest for DTCs P0601, P0602, P0603, P0604, and P062F.

### Circuit/System Testing

Reprogram the TCM and recheck for DTCs.

⇒ | If the DTC resets, replace the control solenoid (w/body and TCM) valve assembly.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Perform the Service Fast Learn Adapts if internal transmission repairs are performed.