The code P0715 is defined as: “Turbine/input speed sensor circuit malfunction.” This means that the transmission cannot read the engine RPM, preventing it from shifting correctly and causing an erratic and difficult transmission.
P0715 is a generic fault code, which can be applied to all vehicles equipped with the OBD-II system. And although the definitions are different between brands, they all refer to the same failure in that system.
Transmission Input Sensor Operation
You will find this sensor near the rear of the torque converter, threaded directly into the transmission case. You will see specially designed slots on the input shafts. The input shaft completes the electromagnetic circuit by passing very close to the final sensor.
As the slots pass the sensor, the circuit intermittently forms an electronic pattern. The PCM receives this pattern as a waveform pattern, which it also understands as the transmission input speed.
If the actual input speed changes and does not match the desired input speed, a code P0715 and a fault light will come on.
The P0715 code indicates that there is a problem with the input speed, or there are problems with the sensor and its signal. The most common solution is to replace the sensor or the damaged wiring harness since the transmission has a fairly high reliability.
However, this code can also be activated because the ATF transmission fluid is dirty or in poor condition. In any case, a prior diagnosis must be carried out before proceeding with repairs.
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What Is Code P0715?
This fault code refers to the PCM detecting a fault in the transmission input sensor signal. It may be that the signal is non-existent or outside the parameters.
If the signal is non-existent, it means that the problem may be in the sensor itself or in its cable branch. On the other hand, if the sensor is out of parameters, the situation is a little more complex because it can indicate internal problems in the transmission.
It may also happen, although in very few cases, that there is a communication problem between the TCM and the PCM. All the faults that you can associate with code P0715 have the transmission and its control system as a common source.
Of course, to diagnose it, you must start with the simplest and most practical thing to do, checking the ATF oil. From there, start to check all the components.
Common Symptoms of Code P0715
Because this error code is related to the transmission, in some cases the PCM is placed in “Engage” mode, causing the transmission to shift harshly and irregularly.
Therefore, it is important to address this issue as soon as possible. Some of the most common symptoms include:
- Erratic or hard shifting of gears.
- Higher fuel consumption.
- The transmission does not change.
- Fluctuation in the speedometer.
- Failure of the speedometer to function.
- The engine turns off when the car is stopped.
Possible Causes of Code P0715
Error code P0715 It usually presents a primary cause along with secondary problems that are less common. These include:
- Defective transmission speed sensor.
- Faulty or damaged speed sensor wiring.
- Defective shift solenoid.
- Faulty speed sensor electrical connection.
- Damaged transmission valve body.
- Dirty transmission fluid.
- Low-level transmission fluid.
How to Diagnose Code P0715
This error code is quite easy and straightforward to diagnose. By definition, this code is specific and refers to a particular system, the transmission.
Let’s look at the diagnostic steps.
1. Check the ATF transmission fluid
The first thing you should do is check the condition of the ATF transmission fluid in your system. It must be level and the liquid must be in good condition.
If it is not at the correct level, complete it. If the fluid is in poor condition, dirty or has lost viscosity, it is best to extract all that oil and change it with new ATF fluid. You should also change the transmission oil filter when you perform the ATF change.
Many times the failure is resolved only by topping up the fluid level or changing it with new ATF oil.
2. Connect the scanner
Then you must connect the OBD2 scanner to check which code is activated. This P0715 code may be accompanied by other transmission-related codes.
Take note of all the data and codes on your scanner and delete everything. Then do a test drive and start to see if the code comes back.
If the code does not return, you have an intermittent problem. You must wait for the code to appear again. If the code appears, you should begin your visual inspection at the input speed sensor.
3. Check the status of the input sensor
You must determine the wiring condition, both of the sensor itself and of the entire system. Any damage should be repaired or replaced as necessary.
Next, test the sensor’s voltage and ground wiring to see if there is an unseen fault in the wiring or a problem with the sensor itself. If you detect a wiring problem, you should replace the wiring harness. If you detect problems with the sensor, you must replace it.
4. Transmission check
If you check the entire system, and it is in order, the problem may be inside the automatic transmission. As it is a more complex failure, you should take it to a specialized service for a more in-depth diagnosis.
There, they will disassemble the transmission to perform the diagnosis and check the operation of the solenoids and actuators. This may be a major repair.
How to Fix Code P0715
Check your vehicle’s technical service bulletin. The problem can be known and the manufacturer can fix it, saving time and money during the diagnostic process.
This error code is generally easy to fix, and three of the most common solutions are:
- Replacing the input speed sensor.
- Repair damaged wiring in the input speed sensor.
- Replacing the ATF transmission fluid.
Transmission fluid leaks that are not fixed after replacing the cables and/or sensors can cause serious damage to the input speed sensor cables. If this happens, the sensor will definitely fail again.
Note that error code P0715 It affects different makes and models of vehicles differently. Some will show noticeable symptoms, while others will prevent the transmission from shifting.
An automatic transmission that won’t shift will not only cause inconvenience but can also pose safety issues when driving, which can be quite dangerous.
Is Code P0715 serious?
Yes, we can say that this code has high gravity. The transmission will operate erratically or not at all. There is a high risk that the car will turn off, not start, and leave you stranded.
Driving with this code activated can affect other transmission components, worsening symptoms and increasing the cost of repair.
Furthermore, it is not safe for other drivers or for you to drive the car in these conditions.
Common Errors When Diagnosing Code P0715
The input speed sensor wiring can be damaged due to transmission fluid leaks that are not repaired in time. Changing the sensor without carrying out the proper diagnosis is one of the most common errors with this failure.
You must inspect everything, according to the steps described in the diagnosis. You must repair according to these results, do not change parts and components without checking their operation.
Another common mistake is not checking the condition of the ATF fluid. Many times it happens that the liquid is not viscous enough or is contaminated, and it affects the inlet velocity.
The sensor detects this anomaly, sends the signal to the PCM, and the code is activated. In this case, the code is resolved by changing the ATF oil for one in good condition, and one recommended by the manufacturer.
How to Avoid Code P0715?
In some cases, failure may be unavoidable, such as sensor failure due to exhaustion or age. However, there are other failures that you can avoid only with routine inspection and preventive maintenance actions.
For example, checking the state of the ATF fluid and its level from time to time can prevent this fault code. Additionally, you must change this oil within the time stipulated by the manufacturer.
Checking the condition of the cables and replacing the damaged ones before the code is activated is also a good preventive action.
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The code P0715 It is usually accompanied by serious symptoms in your transmission, which will not allow you to drive normally. Ideally, you should take your car for repair and diagnosis immediately, to avoid further damage to the transmission.
Of course, checking the ATF fluid and the system wiring are actions that you can perform in your own garage, as long as you have the necessary knowledge and know what you are doing.
If not, take your car to a technical service specializing in automatic transmissions.
If you want to know other articles similar to Code P0715: Input/Turbine Speed Sensor Circuit Malfunction you can visit the category Fault Codes.