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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 Terrain 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC P0601-P0604 or P062F

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 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 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

The TCM has detected a non-volatile memory error during power-down.

Action Taken When the DTC Sets

P0601, P0603, P0604, and P062F

    • DTCs 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 an immediate landing to 2nd gear.

P0602

    • DTC P0602 is a type A DTC.
    • 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

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

Reference Information

Description and Operation

Refer to Electronic Component Description for control solenoid (w/body and TCM) valve assembly 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. Let the engine run for at least 1 minute.
  2. Ignition OFF for at least 30 seconds to allow for the complete shutdown of the TCM.
  3. Ignition ON, verify that DTC P0602 is not set.
    4. ⇒If the DTC is set, program the transmission control module (TCM). If the DTC resets, replace the control solenoid (w/body and TCM) valve assembly.
  4. Observe the DTC information with a scan tool. DTCs P0601, P0603, P0604, and P062F should not set.
    5. ⇒If a DTC sets, replace the control solenoid (w/body and TCM) valve assembly.
  5. Observe the DTC information with a scan tool. If DTC P0601, P0603, P0604, or P062F are set, replace the control solenoid (w/body and TCM) valve assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    • Refer to Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.
    • Perform the Service Fast Learn Adapts following all transmission related repairs.