Transmission Scanners – Are They Worth It?

Transmission Scanners - Are They Worth It?

If you’re having problems with your car’s transmission, you might be keen to diagnose the problem yourself, and perhaps even fix it if you’re good at car DIY. This can be done with the use of a transmission scanner.

What is a transmission scanner? This is a small diagnostic device that can retrieve codes from the car’s transmission so that you can find out if there are any faults in it.

With that in mind, let’s explore everything you need to know about transmission scanners. We’ll also look at if they’re worth purchasing. 


How Does A Transmission Scanner Work?

How Does A Transmission Scanner Work?

The way a transmission scanner device works is that data from the transmission system will be sent to the scanner via transmission sensors.

These include speed, throttle, and fluid temperature sensors. When they detect the input, speed, and output of the transmission, they transmit the data to the transmission control unit.

This processes the information to conduct functions such as engaging gears. A transmission scanner device will work to retrieve that data.

Some high-quality transmission scanners will allow you to read live sensor data.

This can single out any sensors that aren’t working properly so that you can replace them, therefore helping you to stay a step ahead of any transmission problems that your car will encounter.

What You Need To Bear In Mind About Transmission Scanners

What You Need To Bear In Mind About Transmission Scanners

While a scanning tool that communicates with your car’s on-board diagnostics can be valuable to give you information about it and what’s wrong with your car, it’s not very useful if you can’t process and understand it.

A generic scan tool won’t be the same as high-quality ones that will give you more options.

It’s worth knowing that a scan tool from the manufacturer will give you many options but it won’t cover vehicles other than those of the manufacturer.

On the other hand, a generic tool might have fewer functions available, but it will be compatible with more vehicles. 

Can You Use An OBD Scanner? 

What You Need To Bear In Mind About Transmission Scanners

If you have an On-Board Diagnostic (OBD) scanner for your car, you might wonder if you can use it to find errors in your transmission. Some OBD scanners do offer this feature.

However, sometimes even OBD2 scanners that can read transmission fault codes are only half the battle won because you won’t necessarily be able to repair the problem easily.

In addition to that, car transmission issues might not show up via a check engine code so the use of such a scanner won’t always give you the information you need. 

How To Use A Diagnostic Tool

How To Use A Diagnostic Tool

If you’re wondering how to use an OBD2 scanner to get information about transmission fault codes, here’s what you need to do. Plugin the scanner to the OBD port, turn it on, and then let it scan.

If you’re looking specifically for transmission problems, it’s worth knowing that the first letter of the fault code that will be on display will be “P” for powertrain, as that signifies a problem with the engine and/or gearbox.

Then, there will be a number that shows up, either “0” for Generic Fault or “1” for Manufacturer-specific code.

The second number will tell you if your faul is really the transmission or something else. Look for “7,” “8,” or “9,” as these all point to the transmission or gearbox having a problem.

Some common transmission codes that you’ll find on OBD scanners include the following:

  • P0218. This means there’s a problem with the temperature being too high, which can be caused by leaky transmission fluid.  
  • P0714. This also refers to high temperature, and it’s common with sensors that need to be changed or dirty transmission fluid that should be replaced. 
  • P0705. This code means that there’s a problem with the range sensor, so the car is likely not to start or shift gears. 
  • P1824. This fault code refers to the transmission range selector. You will need to adjust the shift cable. Alternatively, the internal mode switch has malfunctioned.

How To Tell If Your Transmission Has A Problem Without A Scanner

If you don’t have a transmission code scanner handy, you can still check for any problems with your car’s transmission. Here’s how to go about it. 

Check the engine light


Many problems with the transmission will cause your “check engine” light to come on. So, if you see warning lights on your dashboard, it’s best to nip any problems in the bud by taking your car to your mechanic.

Check the transmission fluid

You’ll have to start your car and put it in park, then open the hood and find the transmission fluid.

Pull out the dipstick that covers it so you can check that the fluid is at the correct level and that it’s the right color. FYI, transmission fluid needs to be clear and red in color.

If it’s dark or brown, then the fluid probably needs to be changed because it’s too old and dirty.

Note that if you have a manual transmission, you will need to check the level of the fluid at the transmission case, via a fill plug and not with a dipstick under the hood.

Notice any leaks


Linked to the above point, you might actually see some transmission fluid leaking out of your car.

If it’s red in color and smells sweet, this is a red flag that it’s coming from the transmission.

Press down the brake pedal

When the car’s on and still in park, press the brake pedal with one foot while stepping on the accelerator with the other. This revs the engine for a few seconds.

Doing this will show you that the engine can rev up properly and the car tries to move forward. If it doesn’t or it can’t rev for a long time, then the transmission could be having a problem.

Check the gears

While you drive, you can tell if there’s a problem with your transmission by paying attention to what happens when you shift gears. In fact, gear-related problems usually indicate transmission problems.

When you change gears, this should occur smoothly. If there’s any jerking, vibration, or high RPMs, then your car could have a problem with its transmission.

Another thing to look out for is what’s known as slipping gears. This is when the gears move in and out of place while you’re driving. It can be dangerous, especially if you’re driving in traffic.

Finally, if the gears grind or shake when you change them, that’s also a sign of a transmission problem.

Notice any burning smell

If there’s a burning smell coming from your car, this indicates you should take your car to a mechanic right away because it can point to an overheating transmission or transmission fluid that is old and becoming burnt. 

Is A Transmission Scanner Worth It?

Is A Transmission Scanner Worth It?

If you’re not a mechanic, you might wonder if a transmission scanner or OBD2 scanner that has transmission functions is really worth purchasing.

You won’t be using it regularly, after all. But if you’re interested in being able to better understand your vehicle and potential problems it could face, such a diagnostic tool can come in handy.

It’s worth knowing that you will need to understand what the fault codes mean so that you have a better idea of what’s wrong with your car.

However, this still won’t necessarily give you a clear indication of what’s wrong; it will usually just point you in the right direction. 

Related Questions 

How much does it cost to remanufacture your transmission?


If your transmission is so damaged that it needs to be remanufactured, you can expect to pay between $1,300 and $3,400 for this service, depending on the model and make of your car.

Labor costs can vary between $400 and $800.

What does it mean to remanufacture a transmission?

This refers to restoring the transmission so it returns to factory standards and is as new as possible. 


Having a transmission diagnostic tool can come in very handy if you want to be able to find out what the problem is with your car.

The benefit of using an OBD2 scanner is that it will usually offer other useful features.

However, there are other ways in which to tell if there’s a problem with your car’s transmission.

In this article, we’ve outlined what a transmission scanner is and how it works, as well as how you can detect transmission problems yourself without one.


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