P0725: Engine Speed Input Circuit Malfunction

It is no secret that car diagnosis and repair can be a daunting task. Fortunately, car makers took steps to make the process a little easier. Nearly all modern cars include an on-board diagnostic system, which you can use to know exactly what is wrong with your car. However, this system still requires a little technical knowledge to use. If you received an OBD-II scanner error code P0725 problem, then that means there is a problem with one of your car's sensors. With our guide, you can learn exactly what this means for your car, what you can do to fix it, and a little bit more about your car in the process.

What Does P0725 Mean?

So exactly what does the code P0725 mean? There is a part of your car called the powertrain control module, or PCM. This controls the cylinder head and other parts of the engine and transmission. The PCM uses a series of sensors to do its job. The P0725 error code specifies a specific sensor in the PCM has malfunctioned. The sensor that has malfunctioned has three names:

  • Engine speed input sensor
  • Transmission input speed sensor
  • Input speed sensor
    • Different sources may call this sensor any one of these names, but they all refer to the same thing. If the PCM does not receive an acceptable signal from the sensor, then it will output this error code. If you receive error code P0726, P0727, or P0728, it also means this sensor is malfunctioning, but these codes give additional information, letting you know if it is a problem with the range or if the signal is coming intermittently or not at all.

What are the Symptoms of P0725?

If the input speed sensor fails, it means your car does not know how fast it is moving, which can cause many systems to fail. The symptoms can include:

  • Failure to shift gears
  • Malfunctioning speedometer
  • Malfunctioning tachometer
  • Slipping transmission
  • Check engine light turns on

The Potential Danger

You can probably tell that all of these symptoms can be dangerous. This issue limits your ability to safely drive your car and you should not ignore the error code. Additionally, this problem may result in damage to the transmission, which is one of the most expensive vehicle components to repair or replace. Replacing a sensor is check and easy, so you should consider this error code your warning before more serious damage is done to your car.

How to Fix P0725

Naturally, you are probably wondering, “How do I fix trouble code P0725?” It depends on what causes the malfunction in the first place. Chances are very high that the error code is a result of a faulty sensor or circuit. If the sensor itself is damaged, then it makes sense that it would send this error code. There may also be metal deposits on the sensor. However, the problem may be electrical in nature, rather than mechanical. If the circuitry or connectors are damaged, then the PCM would still not receive any signal from the fully-functional sensor. You can use special tools to get more information from the car. If the PCM is receiving an inappropriate signal from the sensor, rather than no signal at all, then it is not an electrical issue.

Unfortunately, sometimes this error code can be caused by a failing transmission. If neither the sensor nor circuitry is failing, you should turn your attention to the transmission. If this is the issue, then you will likely have to take your car to a mechanic. Working on the transmission is very complicated and only people who are trained to do it should attempt to do so. If you do not know what you are doing, you might damage your transmission further.

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