This procedure covers the removal and replacement of the Transmission Control Module (TCM) on a 2018-2024 Toyota Camry with the 2.5L I4 engine and automatic transmission.

Warnings

Tools required

Parts

• Transmission Control Module × 1 — Use OEM specification
• Cover screws (if damaged) × 4 — 90159-50083

Preparation

1. Ensure the vehicle is parked on level ground with the parking brake engaged
2. Turn the ignition off and remove the key
3. Open the hood and support it with the prop rod
4. Disconnect the negative battery terminal and wait at least 3 minutes before proceeding
5. Allow the engine and transmission to cool to ambient temperature if recently driven

Procedure

1. 1

   Access the TCM location
   The TCM is located on top of the transmission, accessible from the engine bay on the driver's side. Remove the engine cover by pulling upward on the cover to disengage the mounting grommets. Set the cover aside.
2. 2

   Locate the Transmission Control Module
   Identify the TCM mounted on the upper portion of the transmission case near the battery tray. It is a rectangular metal module with a large multi-pin electrical connector and typically has a protective cover secured with screws.
3. 3

   Remove the TCM protective cover
   Remove the screws securing the TCM protective cover using a Phillips screwdriver or appropriate socket. There are typically 3-4 screws. Carefully lift the cover off and set it aside. Note the orientation of any sealing gasket or insulation.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
4. 4

   Disconnect the TCM electrical connector
   Locate the connector lock mechanism on the large multi-pin connector. Push or slide the connector lock tab to release it (typically a sliding tab on top). Firmly grasp the connector body and pull straight away from the TCM while wiggling gently if needed. Do not pull on the wiring harness. Minor transmission fluid seepage is normal.
   ⚠Do not touch the connector pins on either the TCM or harness. Contamination or damage to pins will cause transmission malfunctions.
5. 5

   Remove TCM mounting fasteners
   Remove the bolts securing the TCM to the transmission case using a 10mm socket. There are typically 2-3 mounting bolts. Keep track of any washers or spacers. Note the exact position and orientation of the TCM for reinstallation.
6. 6

   Remove the TCM from transmission
   Carefully pull the TCM straight away from the transmission case. The TCM may have a short shaft or alignment pins that insert into the transmission valve body. Pull evenly to avoid binding. Once removed, inspect the O-ring seal on the TCM connector port for damage. Wipe away any excess transmission fluid with a shop towel.
7. 7

   Prepare the new TCM
   Remove the new TCM from its protective packaging. Inspect the O-ring seal on the connector port - it should be clean and properly seated in its groove. If the new TCM includes a new O-ring, carefully remove the old one from the transmission case port and install the new one, ensuring it is not twisted or damaged. Lightly lubricate the O-ring with clean ATF if desired.
8. 8

   Install the new TCM
   Align the TCM with the mounting holes and any alignment pins or shaft with the transmission case opening. Carefully push the TCM into position, ensuring the O-ring seats properly without pinching. The TCM should sit flush against the transmission case.
9. 9

   Install TCM mounting bolts
   Install the TCM mounting bolts and tighten by hand initially. Tighten the bolts evenly in a criss-cross pattern to the specified torque. Ensure the TCM is seated squarely against the transmission case before final torquing.
10. 10

    Reconnect the electrical connector
    Inspect the connector on the wiring harness for any dirt, corrosion, or bent pins. Align the connector with the TCM and push firmly until it clicks into place. Ensure the connector lock tab engages fully to secure the connection. Gently tug on the connector to verify it is locked.
11. 11

    Reinstall the protective cover
    Position any insulation or gasket material in its original location. Place the protective cover over the TCM and install the screws. Tighten the screws evenly to the specified torque in a criss-cross pattern to avoid warping the cover.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)
12. 12

    Reconnect the battery and perform initialization
    Reinstall the engine cover. Reconnect the negative battery terminal. Connect a Toyota diagnostic scan tool to the OBD-II port. Follow the manufacturer's procedure to register or initialize the new TCM. This typically involves VIN programming, transmission type registration, and clearing any stored fault codes. Consult Toyota TIS or equivalent professional scan tool documentation for specific initialization procedures.
    ⚠️The vehicle may not shift properly or may not move at all until the TCM is properly programmed and initialized. Do not attempt to drive without completing this step.

Reassembly

1. Verify all electrical connections are secure and locked
2. Ensure no tools or parts were left in the engine bay
3. Check transmission fluid level after initialization and test drive - top off with Toyota WS ATF if needed
4. Reinstall engine cover properly onto mounting grommets

Verification

• Turn the ignition to ON position and verify no warning lights remain illuminated after initialization
• Using the scan tool, verify the new TCM communicates properly and shows no active fault codes
• Start the engine and allow it to idle - verify the transmission engages Park properly
• Perform a controlled test drive on a safe road, verifying all gear shifts occur smoothly in both Drive and Reverse
• Monitor for proper shift points, shift quality, and check engine or transmission warning lights during the first 20-30 miles of driving
• Note that the transmission may exhibit slightly firmer or different shift characteristics for the first 50-100 miles as adaptive learning occurs

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