When transmissions start shifting hard or fail to shift altogether, many people start thinking of changing the whole thing and getting on with their lives.
Sometimes, this is unnecessary overkill. You might be experiencing transmission problems because you haven’t changed the fluid in a while, have faulty solenoids, or your transmission control module is acting up.
Today, we will look at how you can narrow your transmission problems to the control module and some things you can do to reset, reprogram or replace it.
What is a Transmission Control Module?
This is a computing unit that will gather data from different parts of the car like the brake system, the engine, transmission fluid temperature sensors, the throttle, and turbine sensors and use it to implement gear shifts.
In more advanced vehicles, it can take data from other sensors or vehicle control modules and use it to either shift into appropriate gears or lock you out of the transmission system if you are attempting a dangerous maneuver.
If the module isn’t working right, your gears won’t shift at the right time. The problem might be so subtle that you don’t notice it until it wears down your transmission or so obvious that it interferes with the vehicle’s driveability.
Signs Of a Bad Transmission Control Module
Some of the top signs and symptoms of a failed or failing TCM on your Chevy include:
- The transmission shifts unexpectedly
- Trouble shifting into higher gears
- Delayed shifting
- Bad fuel economy
- The transmission remains stuck in neutral or first gear
- The transmission does not shift at all
- You have a check engine light
How to Reset Your Transmission Control Module
Before thinking of advanced solutions like replacing the control module or taking your vehicle to a credited mechanic, you can try the following free reset procedure on your Chevy. Note that this is a general procedure. The specifics might vary from one Chevy to another.
- Turn the ignition to the ON position.
- With the car still ON but not started, press the gas pedal all the way down.
- Hold the gas pedal down for around 10 seconds.
- With the gas pedal still down, Turn the ignition off. Don’t remove the key from the ignition if you have a key ignition.
- Release the gas pedal
- Wait for three minutes before cranking your vehicle and going for a 30-minute drive.
If this doesn’t work, repeat the procedure but at step 4, remove the key from the ignition (if your vehicle has an ignition.
If the above procedure doesn’t work, you can opt to do a hard reset to all the control modules and electronics in your vehicle. The only disadvantage is that you lose any custom settings – especially in the infotainment system.
ProTip: The alternative is using the user manual to find your Transmission Control Module fuse location. Remove the necessary fuses and let the system stay unpowered for up to an hour to drain the residual charge and reset it before popping back the fuse/fuses.
- Turn your vehicle off and pop the hood.
- Disconnect the car battery starting with the negative cable and then the positive
- Drain any lingering charge in the system by pressing and holding the horn for some three seconds
- Wait for five minutes before reconnecting the battery-positive cable first.
If you are still having transmission problems even after the reset, then you could be facing different problems like:
- A faulty control module that needs rebuilding, reprogramming, or replacing
- Faulty TCM wiring
- A bad ground
- Low transmission fluid
- A faulty transmission
Will a Bad Transmission Control Module Throw an Error Code?
Faulty transmission control modules throw a couple of errors that you can pull with a good OBDII scanner. This should be your first stop, especially if you have a check engine light. Otherwise, the shifting problem could be a result of something else.
The most common errors to expect include:
- P0613
- P0700
- P0706
- U0101
What Ruins Transmission Control Modules?
Damage to the TCM is very rare. If it happens, it was most likely caused by:
- Water damage short-circuiting the circuitry
- Too many vibrations and thermal stress
- A short circuit to the actuators or solenoids
- The damaged circuit connecting to the TCM
- Voltage overload caused by jumping the vehicle wrong or welding with the car battery connected
Can a Transmission Control Module be Reprogrammed?
Only new transmission control modules need programming. The programming must be from the car’s ECU to ensure that the new module works perfectly with the rest of the system.
Never try to program an ECU into your vehicle if you are not skilled or confident of what you are doing, as this could lead to premature or catastrophic failure.
Reprogramming an old TCM already incorporated into the vehicle is unnecessary. They never lose their programming unless the control module is damaged.
What Does Lost Communication with TCM Mean?
Lost communication with the TCM denoted by the diagnostic code U0101 means the TCM is not transmitting or accepting transmission from the CAN bus. Failure to communicate technically renders the TCM unusable.
Some of the causes of the U0101 error code are:
- A faulty TCM
- Malfunctioning TCM circuitry
- A very low battery
- A faulty ground
- A bad sensor corrupting the CAN bus
Resetting your TCM can be a good shot at fixing your transmission problems. This, coupled with regular servicing of the transmission (after 40,000 miles or as recommended by the manufacturer), will give your transmission a very long lifespan.