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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 TrailBlazer - 4WD 🢒 Engine 🢒 Engine Electrical 🢒 Transmission Control Module Replacement

Transmission Control Module Replacement LL8


Object Number: 1926584 Size: MF

Callout

Component Name

1

Transmission Control Module (TCM)

Procedure

A new TCM requires programming. Refer to Control Module References .

Tip

    • Disconnect the TCM electrical connector.
    • Twisting or tilting of the transmission control module electrical connector while disconnecting may result in bent or misaligned electrical terminal pins.
    • It is recommended that transmission adaptive pressure (TAP) information be reset. Resetting the TAP values using a scan tool will erase all learned values in all cells. As a result, The engine control module (ECM), powertrain control module (PCM) or TCM will need to relearn TAP values. Transmission performance may be affected as new TAP values are learned. Reset the TAP values. Refer to Transmission Adaptive Functions .

2

TCM Bracket Nut (Qty: 2)

Notice: Refer to Fastener Notice in the Preface section.

Tighten:
6 N·m (53 lb in)

3

TCM Bracket

Transmission Control Module Replacement LH6

Service of the transmission control module (TCM) should consist of reprogramming of the TCM. If the diagnostic procedures call for the TCM to be replaced, the replacement TCM should be checked to ensure that the correct part is being used. If the correct part is being used, remove the faulty TCM and install the new service TCM. The replacement TCM must be programmed.

Removal Procedure
  1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
  2. Disconnect the cooling fan electrical connector for additional clearance while removing the TCM.

    3. Object Number: 1521469 Size: SH
  3. Depress the engine control module (ECM)/TCM cover retainers (2).
  4. Remove the ECM/TCM cover from the ECM/TCM bracket (1).

    5. Notice: Refer to Handling Electrostatic Discharge Sensitive Parts Notice in the Preface section.


    Object Number: 1521481 Size: SH

    Important: It is not necessary to disconnect the TCM electrical connectors in order to remove the TCM from the ECM/TCM bracket. Only disconnect the electrical connectors if servicing of component requires disconnecting of the electrical connectors.

    Important: Remove any debris from around the TCM connector surfaces before servicing the TCM. Inspect the TCM module connector gaskets when diagnosing or replacing the TCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the TCM.

  5. Disconnect the TCM electrical connector (1) from the TCM (2)

    6. Object Number: 1521482 Size: SH
  6. Release the bracket TCM retainer (1).
  7. Tilt the TCM (2) away from the ECM/TCM bracket.

    8. Object Number: 1521496 Size: SH
  8. Remove the TCM (1) from the TCM bracket (2).

    9. Object Number: 1521468 Size: SH
  9. Only when replacement of the ECM/TCM bracket (2) is necessary, remove the ECM (3). Refer to Engine Control Module Replacement.

    10. Object Number: 1521466 Size: SH
  10. Remove the ECM/TCM bracket retaining bolts (2).
  11. Remove the ECM/TCM bracket (1) from the vehicle frame.

Installation Procedure
  1. If the ECM/TCM bracket (1) was previously removed, install the ECM/TCM bracket (1) to the vehicle frame.

    2. Object Number: 1521466 Size: SH
  2. Install the ECM/TCM bracket retaining bolts (2).

    3. Notice: Refer to Fastener Notice in the Preface section.

  3. Tighten the ECM/TCM bracket bolts.

    4. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1521468 Size: SH
  4. If the ECM was previously removed from the ECM/TCM bracket (2), install the ECM (3). Refer to Engine Control Module Replacement.

    5. Object Number: 1521496 Size: SH
  5. Insert the TCM (1) into the retaining slot of the ECM/TCM bracket (2).

    6. Object Number: 1521482 Size: SH
  6. Secure the TCM (2) to the ECM/TCM mounting bracket ensuring the TCM retaining tab (1) is fully engaged.

    7. Object Number: 1521481 Size: SH
  7. Connect the ECM electrical connector (1) to the TCM (2) if previously removed.

    8. Object Number: 1521469 Size: SH
  8. Install the ECM/TCM cover (2) to the ECM/TCM bracket (1).
  9. Ensure the ECM/TCM cover retainers (2) are fully engaged with the ECM/TCM bracket (1).
  10. Connect the cooling fan electrical connector.
  11. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
  12. If the TCM was replaced the replacement TCM must be programmed. Refer to Control Module References .