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 Descriptor

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. These DTCs are Type A DTCs.

### Conditions for Running the DTC

The TCM runs the program to detect an internal fault when the engine is running. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.

### Conditions for Setting the DTC

The TCM has detected an internal malfunction.

### Action Taken When the DTC Sets

• | DTCs P0601, P0602, P0603, P0604 are Type A DTCs.

• | The TCM commands second gear.

• | The TCM commands maximum line pressure.

• | The TCM commands HSD1 and HSD2 OFF.

• | The TCM forces the TCC OFF.

• | The TCM inhibits the TCC solenoid.

• | The TCM freezes transmission adaptive functions.

#### P062F

• | DTC P062F is a Type A DTC.

• | The TCM commands HSD1 OFF.

• | The TCM commands maximum line pressure.

• | The TCM freezes transmission adaptive functions.

### Conditions for Clearing the DTC

DTCs P0601, P0602, P0603, P0604 and P062F are Type A DTCs.

### Diagnostic Aids

DTC P0602 indicates the TCM is not programmed.

### Reference Information

#### Schematic Reference

Automatic Transmission Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Transmission General Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Transmission Control Module Scan Tool Information

### Circuit/System Verification

Verify that DTC P0602 is not set.

⇒ | If DTC P0602 is set, program the TCM.

⇒ | If DTC P0602 is not set, replace the TCM

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

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