The TCM is an important part of a vehicle with automatic transmission, it collects data for the transmission and interprets signals sent to other parts of a vehicle in order to help in the proper timing and how gears shift in the car.
However, in a situation whereby you need to reset the TCM, how do you do? Do you have to disconnect the battery? Will disconnecting battery reset TCM?
No, disconnecting the battery will not reset the Transmission Control Module. You however need a scan tool to reset the TCM.
What is a TCM?
A TCM is the abbreviated Transmission Control Module also known as Transmission Control Unit. The TCM is a part of any vehicle with automatic transmission and is responsible for the transfer of power from the engine to the wheels by calculating when and how to shift gears when the car is being driven.
The transmission control module is usually located in any of the following places in the car; on the side of the transmission, under the car hood, or in the trunk. The location depends on whether you are using an older or newer car version.
When an issue is detected with the vehicle’s transmission, the TCM sends an OBD II code to the vehicle’s computer system. This code will trigger the check engine light thereby alerting the driver to the need to check the vehicle.
More and newer models of cars now come with TCM as it helps to establish a smooth relationship between the transmission system and engine. It improves the quality of the various gear shifting in your automatic transmission vehicle.
According to design, the TCM is able to last the lifespan of a vehicle but just like other parts of an engine, it is also susceptible to damage.
Will Disconnecting Battery Reset TCM?
No, disconnecting a battery will not reset the TCM. In order to reset the TCM, you should have a scan (transmission scan) tool that is capable of telling the TCM to do that.
Although disconnecting the battery even for a minimum of 5 minutes will cause the vehicle systems to reset, the same is not applicable to the Transmission Control Module.
How to Reset a Transmission Control Module
Depending on the type of car you use, there may be a need for you to reset the transmission module every three months or every six months.
Before proceeding with the reset process, you must also understand that some vehicles have more complex systems than others therefore, the resetting process may be quite different from others.
This process is quite easy and can be done at home, however, if you do not trust your ability to do a good job, take your car to an expert.
We will consider a general process of resetting a transmission control module;
Turn the Key Position
Before proceeding with anything, you must first turn the ignition key position. You should do this by putting the key in the ignition and turning it twice.
When you turn twice, all the lights on the dashboard come on. Note that you are not turning the key to start the car but to ensure all the lights come on.
Put Your Foot on the Pedal
Now, you need to put your foot on the pedal and step down on it. Keep your foot on the pedal until you are able to activate the kick-down switch, when this happens you should hear a click sound.
Push the gas pedal past the click. At this point, your foot should be touching the car floor. Let the gas pedal be down for at least 10-15 seconds
Turn off the Key and Release the Gas Pedal
Now that the gas pedal is pushed down, you can turn off the key and then release the gas pedal.
Now You Wait
This part may be hard or fun, depending on how you choose to see it. All you have to do now is wait, just wait to do nothing. Do not use your phone, don’t open the car door, and wait for t least 3-5 minutes.
You are Ready to Drive
Once all the procedure mentioned above is done, the car is ready to be driven. The Transmission Control Module (TCU) and the Engine Control Unit (ECU) will learn how you drive.
This is done by working together and learning your driving pattern. The important part now is, that you should ensure to drive how you usually drive so the transmission will know and react to your throttle input.
Another method of resetting a Transmission Control Module is considered below, this method can be used if you don’t want to go into the car’s computer to have the TCM reset.
For this process, you will need; someone to help and a multimeter
- Disconnect the Negative Terminal from the Battery: This should be done to avoid an electric shock while you are working, in case your hand slips
- Remove the Positive Terminal: Now you remove the positive terminal from the battery and then remove it from the starter solenoid if you haven’t done so.
- Unplug the Vehicle’s Transmission Control Module: If you are not sure of the location check your owner’s manual. The location will vary according to the vehicle model and type.
- Locate a Gray Wire on the TCM Harness Connector: It could have a black and white strip or whatever color your car uses. This wire known as the ‘signal’ wire controls whether your car enters fail-safe mode when in Park or neutral form.
- Connect the Multimeter to the Wire and then Ground it: Put the transmission selector into P for Park or N for Neutral depending on whether you are using automatic or manual. The car should be put in fail-safe mode if the multimeter reads anything lower than 11 volts.
- Start the Car: You can start the car by connecting the battery cables in reverse order then leave for 15-20 seconds. This gives enough time to enter the fail-safe mode.
- Turn the Engine Off: And disconnect the battery cables, now you can leave them disconnected.
- Start the Car Again: Put the key back in the ignition then try to start the car
With all this process, the TCM should be reset and the transmission working properly.
What Does Resetting TCM Do to a Car?
When you reset a vehicle’s transmission control module you are taking it back to its default settings i.e. erasing codes and telling the TCM to unlearn all that it has learned as regards how to react to a vehicle’s throttle input.
Taking the TCM back to its default settings means it will have to relearn a driver’s throttle input with time and act accordingly
Although resetting a transmission control module is easy and can be done at home, some people cannot do it. If you belong to this category of people, take your car to an auto shop