how to reset a subaru TCM

How to Reset a Subaru Transmission Control Module

As a Subaru owner, you may encounter issues with your vehicle’s transmission that require resetting the Transmission Control Module (TCM).

In this comprehensive guide, we’ll explore the various methods for resetting your Subaru’s TCM and discuss the signs that indicate a faulty TCM.

Why Reset Your Subaru’s TCM?

subaru tcm

There are several reasons why you might need to reset your Subaru’s TCM:

  • Rough or erratic shifting
  • Transmission work or repairs
  • Clearing transmission-related error codes
  • Improving overall transmission performance

By resetting your TCM, you can often resolve these issues and restore your Subaru’s transmission to optimal performance.

Methods for Resetting Your Subaru’s TCM

There are four primary methods for resetting your Subaru’s TCM. Let’s explore each one in detail.

Method 1: Gas Pedal Technique

accelerator pedal

  1. Insert the key into the ignition and turn it to the “On” position without starting the engine.
  2. Press the gas pedal down until you feel the kick-down switch engage. Hold for 10-15 seconds.
  3. Turn the ignition off and release the gas pedal.
  4. Wait for 5 minutes without interacting with any electrical systems in your vehicle.
  5. Drive your Subaru normally to allow the transmission to adapt to your driving patterns.

Method 2: Battery Disconnect Technique

disconnect car battery

  1. Ensure all electrical accessories are off and the vehicle is in park or neutral.
  2. Turn the ignition to the “On” position without starting the engine. Wait for 15-20 seconds.
  3. Turn the ignition off and wait another 10-15 seconds.
  4. Disconnect the negative battery terminal and wait for 3-5 minutes for a hard reset.
  5. Reconnect the battery and start the vehicle. Let it idle for a few minutes for TCM recalibration.
  6. Take the vehicle for a test drive under various conditions to allow the TCM to adjust.
  7. Monitor the transmission’s performance for any improvements or need for further diagnostics.

Method 3: Accelerator Pedal Release Technique

accelerator pedal

  1. Before starting the engine, turn the ignition key to the “On” position and press the gas pedal to the floor.
  2. While keeping the gas pedal depressed, turn the ignition key to the “Off” position.
  3. Release the gas pedal.
  4. Wait for about 30 seconds.
  5. Turn the ignition key back to the “On” position without starting the engine.
  6. Fully depress the gas pedal again and hold for 30 seconds.
  7. Release the gas pedal and turn the ignition key to the “Off” position.

Method 4: Using an OBD Scanner

obd scanner

An OBD (On-Board Diagnostics) scanner is a powerful tool that can help you reset your Subaru’s TCM. Here’s how to use one:

  1. Acquire an OBD scanner from your local auto parts store or online retailer.
  2. Locate your vehicle’s OBD port, typically found under the dashboard on the driver’s side.
  3. Plug the OBD scanner into the port and turn it on.
  4. Follow the prompts on the scanner’s screen to navigate to the TCM reset or reprogramming option.
  5. Carefully follow the step-by-step instructions provided by the scanner to reset your TCM.

Note: If you’re unsure about using an OBD scanner or interpreting the results, consult a professional mechanic to avoid causing unintended damage to your vehicle.

Signs of a Faulty Transmission Control Module

Knowing the signs of a failing TCM can help you address the issue before it leads to more serious problems. Here are some common symptoms:

Symptom Description
Rough or Erratic Shifting Your transmission should shift smoothly and predictably. If you experience rough or erratic shifting, your TCM may be to blame.
Check Engine Light While a check engine light can indicate various issues, if it appears in conjunction with transmission problems, it’s worth investigating your TCM.
Limp Mode If your vehicle enters “limp mode,” limiting performance to prevent further damage, a failing TCM could be the culprit.
Unexpected Neutral Shifts If your vehicle randomly shifts into neutral or refuses to shift altogether, it’s a clear sign of a TCM problem.

When to Seek Professional Help

While resetting your Subaru’s TCM can often resolve transmission issues, there are times when it’s best to seek the assistance of a professional mechanic.

If you’re unsure about performing any of the reset methods or if your transmission problems persist after attempting a reset, don’t hesitate to bring your vehicle to a trusted mechanic for a thorough diagnosis and repair.


Resetting your Subaru’s Transmission Control Module can be an effective way to resolve transmission issues and restore optimal performance.

By understanding the various reset methods and the signs of a faulty TCM, you can confidently tackle this task or know when to seek professional help.

Remember, regular maintenance and attention to your vehicle’s performance can help prevent more serious and costly repairs down the road.

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