Mazda 3 TCM Replacement: Here’s How to Save Over $700

Categories: ECM ECU Engine Computer Module

For Mazda 3s that were made in the years of 2006-2014, one of the most common issues is that the transmission control module comes to a point where it doesn’t function quite as it should. While it might seem like the issues you experience could be something else, this is something that you should always consider first.

Before we get into the details, let’s take a step back in history. Up until the 1940s, automobiles had standard transmissions. In the 40s, the introduction of automatic transmissions hit the streets and provided drivers with the ability to easily shift their gears without having to do it manually.

There was a drawback though, automatic transmissions had to rely on a fluid coupling that would allow the transmission fluid to build up so that it could shift the transmission as necessary. While it served its purpose, it did so by sacrificing the vehicle’s power and fuel efficiency.

It wasn’t until the 1980s that automotive technology started to evolve and embrace transmissions that were electronically controlled instead of embracing dated methods. During the 90s, a transmission control unit dedicated to helping the transmission shift increased in usage. Doing so helped automakers embrace an increased amount of power and more efficiency when it comes to fuel consumption.

While these were great strides for the automotive industry, it does have its setbacks such as failing after a certain amount of time. Over the years of providing vehicle owners with refurbished parts and service in our shop located in the Atlanta area, we have seen it to be more common with 2006-2014 Mazda 3s, and buying a new one can become rather costly.

With that said, this guide will take you through all the basics of what a TCM is, Mazda 3 TCM issues, and how you could save $700 or more if you have to replace your Mazda 3 TCM. If you have any further questions, don’t hesitate to reach out to us and we’ll be there to help you every step of the way.

What is a transmission control module (TCM)?

Mazda 3 TCM Repair

Basically, a TCM is an electronic device that helps tell the transmission how it needs to shift depending on the particular situation (going uphill or downhill) as well as the speed that is being maintained. It works closely with many of the other parts of your vehicle as well as other sensors to help ensure a smooth ride during each and every trip.

It also helps determine how much power the vehicle needs to produce as well as how much fuel is used. You will only find a transmission control module in vehicles with automatic transmissions, as it basically replaces the need for the driver to control the clutch when they’re shifting gears.

There are more advanced TCMs on the market that will help remember your driving habits. Doing so will allow it to store information about them and know how it needs to react in terms of gear adjustment. If your TCM goes bad, it could lead to a variety of issues (at times making it difficult to diagnose) which will be covered in the next section.

How to Know If Your TCM Is the Root of Your Troubles

Knowing the issues that a bad TCM in your Mazda 3 could cause will help you understand if it’s truly the root of your problems. Preventing you from having to make unnecessary repairs, or even worse, let it sit because you think that it’s something more serious than what it really is.

Common Failures: 

  • Strong “kick” when switching automatic grip from position “P” to position “R”
  • Indication on the dash “Check Engine” check engine , “AT” check engine, “ABS” check engine, “Slippery Road” (ESP) check engine etc.
  • Gearbox does not go to “manual mode”
  • The car goes in emergency mode only
  • Check Engine light and AT lights are on
  • Vehicle stays in 3rd gear only (safe mode)
  • Hard “kick” on “drive” and “reverse”
  • Hard shifting on gears

· The first sign is the most obvious, your check engine light is on.

While the check engine light for a Mazda 3 could mean a number of things, one of those issues could be the transmission control module itself. If you find that your check engine light comes on it should lead you to either performing a diagnostic scan yourself (with a reliable diagnostic scanner that can produce you with the error codes) or by taking it into a shop (such as the one we have in the Atlanta area) to have a mechanic run the scan and let you know what’s going on.


  • Error DTC U0073 – control Module Communication Bus “A” is off (the e-Data bus control is disabled)
  • Error DTC U0100 – Lost Communication with ECM/PCM “a” error (data bus, engine control module (ECM) “A”-no link)
  • Error DTC U0101 – Lost Communication with TCM (data bus, transmission control module (TCM) – no link)
  • Error DTC P0715 – Input/Turbine Speed sensor “A” Circuit (the rotation frequency sensor of the input shaft of automatic gearbox (Hydrotransformer turbine)- Electrical circuit failure)
  • Error DTC P0720 – Output Speed sensor Circuit error (shaft rotation frequency sensor – fault of electrical circuit)
  • Error DTC P0744 – Torque Converter Clutch Circuit Intermittent (Electromagnetic valve coupling of a hydro transformer – unreliable pin of the electrical circuit)
  • Error DTC P0745 – Pressure control solenoid valve manifold “A” (Gearbox Electromagnetic fluid pressure control valve – electric circuit fault)
  • Error DTC P0748 – Pressure control solenoid valve manifold “A” Electrical Gearbox (electromagnetic pressure control valve – electrical malfunction)
  • Error DTC P0753 – Shift solenoid valve manifold “A” Electrical (Gearbox electromagnetic valve A – electrical malfunction)
  • Error DTC P0758 – Shift solenoid valve manifold “B” Electrical (Gearbox electromagnetic valve B in – electrical malfunction)
  • Error DTC P0763 – Shift solenoid valve manifold “C” Electrical (Gearbox electromagnetic valve C in – electrical malfunction)
  • Error DTC P0768 – Shift solenoid valve manifold “D” Electrical (Gearbox electromagnetic valve D – electrical malfunction)
  • Error DTC P0773 – Shift solenoid valve manifold “E” Electrical (Gearbox electromagnetic valve E in – electrical malfunction)
  • Error DTC P0778 – Pressure control solenoid valve manifold “B” electrical (electromagnetic valve B in pressure control – electrical malfunction)
  • Error DTC P0791 – Intermediate Shaft speed sensor “A” Circuit (intermediate shaft frequency sensor – failure of the electrical circuit)
  • Error DTC P0841 – Transmission Fluid Pressure sensor/Switch “A” error – Circuit Range/performance (sensor A of the pressure of the work fluid of gearbox – band/function)
  • Error DTC P0882 – TCM Power Input Signal Low (Gearbox electronic control module – low power supply voltage)
  • Error DTC P0883 – TCM Power Input Signal Low (Gearbox electronic control module – high power supply voltage)
  • Error DTC P0884 – TCM Power Input Signal Intermittent (Gearbox electronic control module (TCM), input power signal – unreliable pin of the electrical circuit)
  • Error DTC P2709 – Shift solenoid valve manifold “F” Electrical (electromagnetic valve F gear switches – electrical malfunction)

Another way that you can try to uncover what error codes are causing your check engine light to come on is to visit your local parts store. Sometimes they will be able to do a free scan to tell you what error codes are contributing to your check engine light being on.

Keep in mind that this is something that is only available at certain parts stores, as well as for certain makes, models, and years so you will want to give your local parts store a call for more information on their requirements and whether this is even a service that they offer.

· You can’t shift out of neutral or you find yourself stuck in the same gear.

Usually, you will either find yourself stuck in first gear or neutral, causing you to either be limited by the speed of first gear or stuck in place without the ability to go anywhere. The reason that a bad transmission control module can cause this is that no information is being sent to your transmission or the other components that it relies on.

· Your car may seem like it’s not shifting into higher gears properly.

When speed is gradually increased, your vehicle is designed to shift into the gears that it needs to be at for the speed that you’re at. If your RPMs keep going up instead of going down (which is what happens when gears are shifted), your transmission control module could be faulty causing it not to shift into the appropriate gears when they should be.

In cases like this, your gears only have a certain amount of speed that they can go to which means that you might not be able to reach your intended level of speed due to the TCM not allowing it to shift into a higher gear.

· You may notice that your car doesn’t downshift as it should.

In a nutshell, you’ll notice this when you pick up acceleration and then let off of the gas pedal. It won’t be able to downshift like it’s supposed to. Instead, it will keep itself stuck in a higher gear than what it needs to be in for that current moment.

A good example is if you mash on the gas to pass a car that’s moving down the road rather slowly, but after you pass and let off of the gas, your car still seems to be stuck in that higher gear and it seems like it takes longer than it should to shift into a lower gear.

· Fuel consumption may be more than what it normally is.

Any kind of problem with your transmission will result in the timing being off when it comes to shifting into the right gear that ensures fuel efficiency. With a TCM that’s giving you trouble, this timing is off, and your vehicle doesn’t shift as it should. This leads to having to fill up with gas more often, as well as costing you more at the gas pump than you might normally spend.

· Shifting may occur unpredictably without giving you any type of warning.

The transmission control module is the brain of your automatic transmission, and if it’s not working as intended it could cause your transmission to shift improperly. This means that it could shift itself into neutral or into another gear without giving you any kind of warning.

You can imagine how dangerous this could be for you if it does happen, and even cause a serious accident. This is why you need to have your vehicle towed home (if you plan on doing the repair yourself) or to the shop of your choice. The only exception to this if you have a paddle shifter, which will allow you to shift the gears manually and bypass the TCM. Even then, make sure that you park your vehicle until the needed repair is performed to prevent any other types of problems from coming to the surface.

· The time it takes to shift gears may take longer than it normally would.

In fact, this could make you think that your transmission is slipping. If you find your RPMs slipping into the red zone often before it switches gears, the odds are that your TCM is faulty and is causing it to take longer to shift gears than it should.

If this is ignored, it could create unneeded stress on the engine itself and be the onset of further problems that will not only damage the mechanical functionality of your vehicle but cost you a lot more for repairs as well. If this issue occurs, your best bet is to replace the TCM immediately to prevent it from becoming a bigger problem than it has to be.

· Your transmission may be overheating unexpectedly.

When a transmission control module fails to do what it’s intended to do it tends to cause other Mazda 3 transmission issues as well. Leading to forcing the transmission itself to work harder in order to try to ensure that gears are shifted as they should be. When a transmission is overworked, it tends to overheat itself in which case you might smell burnt fluids. ANY TIME THAT THIS HAPPENS, STOP DRIVING IMMEDIATELY.

If you continue to let it overheat, it could lead to complete failure of your transmission which is a bigger issue than it would be if you would have replaced the TCM. In fact, we have seen some vehicles get to the point where the transmission had to be replaced entirely. Whereas if the Mazda 3 TCM replacement was embraced in a timely manner, it wouldn’t have ever come close to needing to be replaced.

· The performance of your vehicle isn’t as good as it normally is.

Not only will a bad TCM in your Mazda 3 affect how your car shifts, but it also can affect your performance directly. From messing up the fuel and air mixture ratio (causing your car to jump) to reducing the overall speed that you can get up to, it can cause quite a headache. Not to mention, the other sensors that rely on it may not be receiving the right communications to operate properly.

· Your engine may stall out unexpectedly without any sort of warning.

As it was mentioned earlier, the transmission control module is responsible for communicating with your other vehicle components to help them function correctly. This includes but is not limited to the charging system as well as the transmission itself. Any time that a module communicated with this many components, it is a critical piece that contributes to the overall functionality of your vehicle.

There are times when we have seen our customers experience their cars stall out due to Mazda 3 transmission issues. While this usually happens after the repair is ignored for an extended amount of time, it is still a risk that no driver can afford to take. Any vehicle that stalls out without warning could lead to putting you in a dangerous situation (especially if it happens on a roadway).

Is it safe to drive with a bad transmission control module?

Absolutely not. The most important reason is that not only could this put you in harm’s way, but it can jeopardize the safety of others on the road as well. With a bad transmission control module in your Mazda 3, your car could shift out of gear without notice (leading to being rear-ended) as well as stall out unexpectedly while you’re driving down the road.

On top of the safety factor, you also have the chance that it could damage the internal components of your transmission as well. What turned out to be a less complex fix could lead to having to do some serious repairs that will not only set you back financially but extend the amount of time that your vehicle will be inoperable as well. Keeping these things in mind, YOU SHOULD NEVER DRIVE UNTIL YOUR MAZDA 3 TCM ISSUES ARE CORRECTED IN THEIR ENTIRETY.

You might be thinking that you don’t have the money to replace the TCM, but the best route is to evaluate your options and see what can be done realistically. The headaches and safety risks that you avoid by doing so will definitely end up being worth their weight in gold.

The Cold Hard Truth About Auto Parts That You Must Know

Gone are the days when automakers would make their parts where they would last for a long time (if not the entire life of your vehicle). Profits have come before quality, and it’s a rather sad situation, to say the least. You can expect your parts to last for only 5-6 years before they start to experience some type of failure, and it’s no different with Mazdas than it is with other vehicles.

The reason for this is that if they can sell more parts, they can sell more service to your vehicle as well which essentially leads to increased profits not only for them as a company, but for their dealerships as well since this is where most vehicle owners will take their cars in if they need to be repaired. While it might not seem like the most ethical thing to do, it’s the dark reality of the world we live in.

Since there is no way to get around it, the best thing you can do is to make sure that your replacement parts are high-quality instead of the lower quality that automakers send out of their factories today. A good approach to this is detailed in the last section of this guide, which will not only save you a ton of money but time as well since you won’t have to worry about it happening again later on down the road.

When you install a new Mazda 3 TCM, it will need to be programmed.

So, you’ve went and got a new transmission control module thinking that it would be the end of a money pit, but unfortunately, when you buy one new it does come with its own set of requirements. Among these requirements is that a brand-new Mazda 3 TCM will have to be programmed specifically to the needs of your vehicle in order to function.

Think of this as another way for dealerships and automakers to generate more income from the owners of their vehicles. In fact, we have seen dealerships charge people several hundred dollars just to program a part to their vehicle. We think it’s ludicrous.

Here at UpFix, we want to save our customers as much money as possible which is why we provide a solid alternative than having to go to the dealership and pay the high cost of Mazda 3 TCM programming. Since we repair the part that was originally on the vehicle, there is absolutely no need to have it programmed. It is a lot more than your local Mazda dealership would offer you, considering it takes away from the revenue that they can generate by making you pay for the programming too.

Here’s how to save over $700 on Mazda 3 TCM replacement. It’s simple!

So now you have come to the conclusion that it’s time to see what options are available when it comes to Mazda 3 TCM replacement. You have definitely come to the right place as we have helped countless people save over $700 in comparison to what it would cost them if they were to go to the dealership.

We’re here to help you save on the number of times that you have to visit the dealership while helping protect the world that we live in by reducing the number of parts found in landfills today. In fact, it’s one of our main focuses that has led to the success that we have gratefully embraced over the years.

There are two options that we have available when it comes to Mazda 3 TCM repair. Our full-service approach allows you to bring your car into our shop located in the Atlanta area to have us handle taking it out for repair and replacing it so that you don’t have to.

The most popular approach we find that is embraced is for those who are looking to do the replacement themselves. All you have to do is call us directly for the information that you need in order to ship your failed Mazda 3 TCM to us for repair by our IPC Certified Technicians (which is a certification our employees hold to ensure the highest level of craftsmanship in the auto industry). Once you have that information, just ship it to us and we’ll fix the issues so that we can send it back your way.

Don’t worry, we’re not the ones to leave you in the dark as we believe our future is best when we help our customers in their time of need. You’ll receive instructions on removing it as well as putting it back in so that you can make sure that the process is as straightforward as it can possibly be. And as it was mentioned before, no reprogramming will be necessary since it will be the same TCM that you pulled out of the vehicle so it will still have all of the information that it needs.

On top of providing you with a more affordable approach to Mazda 3 TCM repair, we stand behind our work with a 1-year warranty. This means if the component fails within a year of having us fix it, we’ll make it right and ensure that it doesn’t happen again. Just think of this approach as an eco-friendly solution that saves you hundreds of dollars on the repair.

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Replacing your failed part with a another used/new one is not always the best solution because the VIN numberodometer mileage, programming will be different and will require additional programming. If it is a used part then you don’t know how long the used replacement part will last. If it is a new part then it will need additional programming. Our repair and return service will save you hundreds of dollars. Once we receive your part, our trained and IPC certified technicians will run tests to identify the source of the problem. We will rebuild your part, replacing not only the failed components, but all components that are usually known to fail or go bad in this part. There is no programming required after we rebuild your original part. The vin number, odometer mileage and vehicle settings are unchanged. We want to make your experience as effortless as possible. All you have to do is send your part to us. Then after receiving the part back from us, just reinstall it and you’re back in business!

Where is the TCM located in a Mazda 3 year 2006-2014

Common part numbers for Mazda 3 TCM:

L539189E1H, L5E4189E1B, L539189E1E, L539189E1F, LF8M189E1F, LF6L189E1, LF8M189E1H, L34T189E1C, L34T189E1D, L539189E1D, LF8M189E1E, L5E4189E1A, L34T189E1A, L539189E1E, L34T189E1E, LF2L189E1F, LF8M189E1D, L5F8189E1A, L32E189E1B, L34T189E1B, L32E189E1D, L3S818881B, L3P618881M, L39C189E1B, L39C189E1C, LFJE189E1D, L23E189E1B, LFJE189E1B, L32E189E1C, LFJE189E1A, LF8M189E1G, LFS3189E1A, LF8M189E1F, LFJE189E1A, L34T189E1A, L34T189E1C, LF8M189E1D, LFJE189E1B, LF8M189E1G, LF8M189E1E, L539189E1H, L5E4189E1E, L32E189E1B, L32E189E1B, L539189E1E, L34T189E1C, L539189E1H, LF8M189E1E, L32E189E1C, L34T189E1A, L34T189E1E, L34T189E1D, L5F8189E1A, LFJE189E1A, LF8M189E1G, LF8M189E1D, L34T189E1B, LFJE189E1D, L539189E1F, L39C189E1B, LF8M189E1F, L539189E1B