Speedometer Not Working and Transmission Not Shifting

A car’s speedometer calculates the car’s speed interaction through the transmission and driveshaft. The car’s computer translates rotational speed into the linear speed of your car, then transmitted to you through the speedometer. There’s a possible risk to drivers when the speedometer isn’t working properly. 

On the other hand, automatic transmission transfers the power to the drive wheels from the engine. Manual transmission fluid transfers engine power to make the meshing gears smooth and connected. No matter what type of transmission you’ve, you won’t be able to go whether your transmission is not shifting.

Any car that’s speedometer not working will be very unsafe and impractical. You can put yourself at risk of an accident by unknowing your speed. Similarly, when transmission is not shifting, you won’t be able to go. So, you must stop driving and find out the reason behind it.

In this article, we’ll discuss in detail why the speedometer not working and transmission not shifting. Our article helps you to find out the reason and solve your car’s problems. Hopefully, you can easily solve the situation with the help of an expert mechanic.

Speedometer Not Working and Transmission Not Shiftingspeedometer not working and transmission not shifting

Causes of Speedometer Not Working:

As its name indicates, a speedometer is an instrument on a car’s dashboard that informs the speed of your car. Knowing the proper speed is essential from a safety standpoint.

Working a speedometer is necessary for safe driving. When you see it’s not working properly you should find out why it’s not working.

Common Causes:

  • Broken Speed Sensor:  Speed sensors have many functions, for example, indicating the car’s speed, and regulating fuel flow. It also operates the cruise control and ignition timing. Once the speed sensor has failed, it can stop the speedometer from working. Additionally, you can also notice that you’re not able to use the car’s cruise control, as a result, your car can’t run smoothly. Also, the faulty speed sensor will commonly come to the Check Engine light on, which indicates that there’s a problem.
  • Bad or Damaged Wiring: Besides, there’s a chance of damage to the wires when it’s exposed to the wet condition. Wet wires can easily short out, the final result is a blown fuse. When the fuse is blown, it can cause the speedometer to fall to zero. In that condition, you have to replace the fuse when it is damaged anyhow.
  • ECU Malfunctioning: The engine control unit (ECU) is called the car’s computerized brain. ECU functions on many important activities, one of them is speed. Once there’s any malfunctioning with the ECU, it must affect the identifying ability of the car’s speed. The result is the speedometer not working suitably.

Solutions of Speedometer not Working:Solutions of Speedometer not Working

Firstly, an expert mechanic examine your 

car by using a code reader/scanner. This scanner scans all error codes or checks whether your car can produce any engine light. Mechanics get an idea of failed components by connecting them to the car’s ECU.

When the mechanic thinks that the speed sensor has broken, he will get underneath the car to find out the sensor location. He checks the sensor and corresponding wires to find any damage to the unit under the car.

Therefore, he will remove the broken one and install a brand new speed sensor.

Additionally, when he suspects that bad or fuse wire can be a possible cause of the issue, he will check out the fuse to find out the problem. Mechanics will replace the fuse when the fuse has been blown.

Moreover, the mechanic will replace the entire Engine Control Unit (ECU) in case he finds any problem with it. Because resetting the ECU is a temporary solution but replacing will ensure that it works longer. In all repairs, the mechanic must be clear about trouble codes by using a code reader/scanner.

Finally, the mechanic will do a test drive to confirm that all systems are functioning and the speedometer has returned to work.

Causes of Transmission Not Shifting: Causes of Transmission Not Shifting

Any car has either automatic or manual types of transmissions. Manual transmissions are sealed units, so you don’t need to check them. Even no need to add transmission fluid directly to the manual transmission. However, you can check and change the transmission fluid to an automatic transmission.

So, we’ll discuss the automatic transmission shifting problems. You can experience a lot of transmission shifting problems, here’s some common reasons.

Common Causes:

  • ECU Malfunctioning: The engine control unit (ECU) works the computerized brain of your car. ECU regulates many factors of car activity. One of the main reasons why your car’s automatic transmission isn’t shifting shall be the bad ECU. It’s recommended to check out the car’s ECU by a mechanic who has expertise in the electrical system.
  • Low or Dirty Transmission Fluid: Transmission fluid roles are very functional for both automatic and manual transmission. No matter what type of transmission you’ve, when your transmission is not shifting, it’s the possibility of transmission fluid. Dirty and old transmission fluid can lose viscosity, collect debris and stop working suitably. So, old transmission fluid needs to be replaced sometimes. Likewise, once your transmission has any leak, then the inside transmission fluid level goes too low, you’ll also face the problems. 
  • Additional Causes of Shift Condition: Although these are mostly responsible for transmission not shifting, there are also additional reasons. For case, bad connection, worn out sensors also lead the transmission to “no shift” condition. So, you have to look at the engine for worn, disconnected or damaged wiring, and blown fuses. Also, have a check at the engine light that comes for problems with the sensors. All of these are responsible for the impossible shifting. 

Solutions of Transmission Not Shifting: Solutions of Transmission Not Shifting

Transmission not shifting can be a dangerous condition for drivers during driving. It’s always suggested to check out the problem with an expert mechanic in that situation.

The expert mechanic examines your car by using a code reader/scanner to scan any error codes or check whether the car can produce any engine light. He can get a clear idea about trouble codes of the car’s ECU by using this scanner.

When the mechanic thinks that the 

The problem is coming for the engine control unit (ECU), he will replace the full ECU as a permanent solution.

Moreover, he can also search for other parts such as damage the wire or blown on fuses. The mechanic will examine the wires to find out any damage. He will fix the wire in case of any damage. Again, when he find a blown fuse, then he will replace the old one with a new fuse 

Furthermore, the mechanic will check the

level of transmission fluid according to your car’s recommended. Dirty, old or lower transmission fluid needs to be replaced. Here are some bestseller transmission fluid of 2021.

In the end, the mechanic will do a test drive to confirm that all systems are properly working and transmission has returned to smooth shifting.


Speedometer not working and transmission not shifting are two common problems that many drivers face. Although they are different components, the causes and solutions are almost similar. Then, always suggest examining your car’s expert mechanic in the problem.

Once the speedometer isn’t working it will be very unsafe and impractical. You can put yourself at risk of an accident by slowing your speed. Likewise, when the transmission is not shifting, you won’t be able to go anywhere with your car.

We’ll discuss in detail all about these two problems so that you can detect your own. You can also solve your car’s problems with the help of expert mechanics. Hopefully, you can easily detect what’s the problem and solve the situation with expert help.

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