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

The internal fault detection is handled inside the transmission control module (TCM). No external circuits are involved.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

The TCM has detected an internal malfunction.

### Action Taken When the DTC Sets

• | DTCs P0601, P0602, 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, except P0602.

• | The TCM commands an immediate landing to 2nd gear, P0602 only.

### 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 30 seconds. Following this procedure will allow for a complete TCM shutdown.

### Reference Information

#### Description and Operation

Electronic Component Description for transmission control module information

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Engine running for at least 1 minute.
2. Ignition OFF for 30 seconds to allow complete shutdown of the TCM.
3. Ignition ON, verify that DTC P0602 is not set.

⇒ | If the DTC is set, program the TCM. If the DTC resets, replace the TCM.

4. Observe the DTC information with a scan tool. DTC P0601, P0603, P0604, and P062F should not set.

⇒ | If a DTC sets, replace the TCM.

5. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed in the Freeze Frame/Failure Records data.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for TCM replacement, setup, and programming.