Transmission Control Module Replacement Cost

Know what price you should pay to get your vehicle fixed.

The average cost for a transmission control module replacement is between $624 and $720. Labor costs are estimated between $35 and $111 while parts are priced between $589 and $609. Estimate does not include taxes and fees.
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What is a Trans Control Module?

Where automatic transmissions used to rely exclusively on mechanical or hydraulic actuation, we now have computerized control over transmissions. This is done by an independent transmission control module (TCM), or a dedicated portion of the powertrain control module (PCM). This will vary by manufacturer, year and model of vehicle. The TCM will communicate with several systems on the vehicle to determine the most advantageous settings for the transmission at any time, and command the crisp and efficient change in settings for the transmission based on pre-programmed settings. Another main function of the transmission control module is to analyze the operation of the transmission to ensure the transmission is working as intended, and to alert the driver when there is an issue. Most of these work of a transmission control module is for automatic transmissions, but note that manual transmissions still require a control module to communicate with. This is for things like vehicle speed, temperature, or even electronic shifting in dual clutch transmissions.

How do Trans Control Modules work?

Transmission control modules are integrated with several other modules on the vehicle, as discussed, and are pre-programed with tables and values which represent the normal operating ranges for the vehicle. The systems the transmission control module may communicate with may be the engine control module, body control module, anti-lock brake system, instrument cluster, traction control system, and even - of all things - the radio. Why does a transmission need to communicate with all of these other devices? Many reasons, for instance, the transmission control module will tell the speedometer how fast the vehicle is moving, it may tell the radio that the speed is great enough for wind noise to drown out the speakers, or it could tell the engine control module to prevent the engine from starting when the vehicle is not in park. This is a small sample of functionality of this powerful, yet overlooked component, but it should provide an idea of how integrated it, and other control modules, have become.

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What are the symptoms of a bad Trans Control Module?

When the transmission control module (TCM) fails, being one of the more important computers on the vehicle, the TCM may make erroneous calculations, fail to connect, fail to operate, or fail to interpret data correctly. This leads to constant malfunctions in transmission operations and several other systems in the vehicle because several systems dependant on TCM data have improper signals from the TCM. This will trigger the check engine light, and the possibilities of on-board diagnostic (OBD) trouble codes stored are endless. However, in many situations, a computerized scanning tool, or a handheld scanner will fail to connect to the transmission control module. The symptoms of the vehicle depend on the impacted systems, and the worst case scenario is a vehicle that cannot be used due to erroneous operation of the transmission.

Can I drive with a bad Trans Control Module?

Failure of the transmission control module is likely to leave the vehicle disabled or only functioning in one or two speeds. Also, the possibility of a safe driving mode being engaged means the vehicle is all but useless until repaired. If the transmission control module fails, it should be replaced and updated before the vehicle continues service.

How often do Trans Control Modules need replacement?

The transmission control module, or powertrain control module, is known to fail frequently in small groups of vehicles, however, failure in most vehicles is not extremely common. Most vehicles will be crushed with the original TCM in place. That is not to say it cannot happen. In fact, as early as 75,000 miles, up to 125,000 miles is the most common range for TCM or integrated PCM replacement for several popular vehicles.

How are Trans Control Module issues diagnosed?

When the TCM is suspected of failure, the particular specifications of that unit must be referenced so the technician knows what the correct readings should be. The TCM will be tested by comparing actual readings to specified readings, following any specific diagnostic steps for that TCM, and confirming diagnosis after each pin has been tested for all necessary parameters. Since there are so many possible failure symptoms, it is not possible to speculate which pin to check, but reference materials will guide the technician through the process of locating the pins/wires that correspond to the issue they are chasing.

How are Trans Control Modules replaced?

Replacing the TCM is normally easy since diagnostics will require the TCM be accessed for diagnostic testing prior to replacement. The technician may need component location reference material to find where the manufacturer installed the TCM. In most vehicles, the transmission control module is in the engine bay, but some manufacturers place the TCM inside the vehicle. In some vehicles, the TCM is even located in the trunk. Once located, any obstructions to testing and replacement must be removed, and testing begins. If the TCM fails diagnostic testing, it will be unplugged, replaced, and reconnected to the vehicle prior to final assembly and testing.

RepairPal Recommendations for Trans Control Module issues

When dealing with electronic systems, especially if the issue pertains to a control module, we recommend thorough diagnostics before replacing parts. In effort to correct an electronic failure, it would be very easy to spend hundreds of dollars replacing components before realizing the issue is more advanced. In the case of electronic failures, diagnostics is a must.

What to look out for when dealing with Trans Control Module issues

The battery connects directly to the engine, meaning it is grounded to the same point as many engine sensors. If the battery is incorrectly installed in a vehicle, such as installing or jump-starting the battery backwards, the TCM can be destroyed, along with some sensors and wiring. In many occasions, the PCM connector, harness, or pins inside the connector socket fail, and cannot make a proper connection to the TCM or transmission. Except for a broken or missing pin, these items can be replaced, and the vehicle retested.

Can I replace the Trans Control Module myself?

Replacing the transmission control module on most vehicles is fairly easy, but accessing the control module usually requires searching behind panels if the component cannot be identified through a vehicle repair database. In many cases, the TCM looks much like a few other computers that are mounted in the vehicle, and removing a few panels to find the wrong module will quickly become frustrating. If proper experience and reference materials are available, the TCM can be replaced, but many will need to be calibrated by the manufacturer. If this process is understood, and it is adapted to the vehicle, this is a money saver. However, if diagnostic procedures are not fully understood, this should be entrusted to a professional.

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