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P0725 OBD-II Trouble Code: Engine Speed Input Circuit Malfunction

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P0725 code definition

The P0725 trouble code detects an issue with the engine speed input circuit.

What the P0725 code means

The P0725 code is a generic OBD-II trouble code that notes a problem with the engine speed input circuit. The engine input speed sensor is responsible for sending a signal about the engine’s speed to the powertrain control module (PCM). The PCM then uses this information to determine the proper shift strategy, which is then provided to the transmission. If the PCM does not receive a signal from the engine input speed sensor, or if the signal is not gradually increasing (which is the expected output), or if the signal is volatile or abnormal, the P0725 trouble code will be triggered.

What causes the P0725 code?

The most common problems that result in the P0725 code are a malfunctioning engine input speed sensor, and a faulty transmission output speed sensor. However, many other things can trigger the P0725 code, including:

  • Corroded, damaged, or shorting wires
  • Loose connectors
  • Dirty or insufficient transmission fluid
  • Malfunctioning engine drivability sensors
  • Faulty shift solenoids
  • In rare cases, a malfunctioning PCM

What are the symptoms of the P0725 code?

The P0725 code will usually be accompanied by an illuminated check engine soon warning light on the vehicle’s instrument cluster. In addition, the car may experience transmission issues, such as an inability to shift smoothly, or even to shift at all. Engine problems may be present as well, including a misfiring engine, hesitation upon acceleration, and occasional stalling. A malfunctioning speedometer and diminished fuel efficiency are common symptoms as well.

How does a mechanic diagnose the P0725 code?

The P0725 code should be diagnosed using a standard OBD-II trouble code scanner. A trustworthy professional mechanic will look at the scanner’s freeze frame data to examine the P0725 code, and to search for any other trouble codes that may also be present. Then the technician will reset the trouble codes, restart the vehicle, and briefly drive the car to see if the codes return. If the codes do not return, the P0725 code was likely triggered erroneously.

If the P0725 code is still detected after being reset, then the mechanic should inspect the wires, connectors, and transmission fluid, to search for any basic and easily resolved issues that may be triggering the code. Whenever an issue is found and resolved, the trouble codes should be reset again to see if the P0725 code persists.

If the P0725 code has proven to be more than just a basic error (erroneous trigger, wires, connectors, or fluid), then the input sensor circuit will need to be examined. The technician will do this by besting the reference voltage and ground signals of the input sensor, and seeing if either circuit is open. Any open circuit should be replaced.

Common mistakes when diagnosing the P0725 code

The most common mistake that is made when diagnosing the P0725 code is a failure to follow the basic OBD-II trouble code diagnosis protocol. The protocol should always be followed in order to ensure that inspection and repairs are both thorough and as timely as possible.

If the OBD-II trouble code diagnosis protocol is not followed, it is common for the input speed sensors to be replaced without proper inspection, when they may not be causing the P0725 trouble code.

How serious is the P0725 code?

In most cases, a vehicle with a detected P0725 trouble code is still very drivable. However, engine and transmission performance will suffer, and there is the risk of further damage being caused to the vehicle.

What repairs can fix the P0725 code?

Some possible repairs for the P0725 trouble code are:

  • Replacement of the input speed sensor
  • Replacement of the output speed sensor
  • Replacement of the wires
  • Replacement of the connectors
  • Replacement of the transmission fluid
  • Replacement of the PCM

Additional comments for consideration regarding the P0725 code

It is common for the P0725 trouble code to be accompanied by an output speed sensor code. It is imperative that a mechanic not only fix the faulty component, but search for greater issues that are causing the damage to the component that needs replacement. This will help keep the issue from quickly resurfacing.

Need help with a P0725 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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