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Error Code P0715 is defined as Input/Turbine Speed Sensor Circuit Malfunction. This means the transmission is unable to read the RPM of the engine, keeping it from shifting properly and causing erratic and hard transmission.
This code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system, or vehicles made since 1996 up to present. Specifications on the definition, troubleshooting and repairs of course, vary from one make and/or model to another.
Error Code P0715 relates to the communication between the PCM (powertrain control module, also called as ECM or engine control module in other vehicle makes) of the vehicle and the TCM or automatic transmission control module. And if the input sensor doesn’t receive signal that is within the specified parameters set by the manufacturer, the transmission will not be able to read the RPM of the engine, causing the Error Code P0715 to appear.
Because this error code relates to the transmission, in some cases, the PCM is placed into “limp-in” mode, causing the transmission to shift harshly and irregularly. Thus, it is important to have this problem addressed as soon as possible. Some of the most common symptoms include:
- Erratic or harsh transmission shift points
- Increased fuel consumption
- Transmission fails to shift
- Fluctuation in speedometer (odometer)
- Lack of speedometer operation
- Engine may stall when coming to a stop
Error Code P0715 usually exhibits one main cause along with secondary issues that are less common. These include:
- Defective transmission speed sensor
- Defective or faulty speed sensor wiring
- Defective shift solenoids
- Defective speed sensor electrical connection
- Damaged transmission valve body
- Dirty transmission fluid
- Low transmission fluid
How to Check
This error code is pretty easy and straightforward to diagnose. First off, technicians conduct a visual inspection of the input speed sensor. This is to determine the condition of the wirings. Any damages must be repaired or replaced as needed
Then, they test the voltage and ground wiring to the sensor to see if there are wiring failure or problem in the sensor itself. If the wiring checks out, the mechanic will replace the sensor, reset the PCM and then take the vehicle for a test drive.
If the problem persists, then the issue may be with the automatic transmission itself.
How to Fix
This error code is also generally easy to fix, and two of the most common solutions are:
- Replacement of the input speed sensor
- Repair of damaged wiring in the input speed sensor
Transmission fluid leaks that aren’t fixed after replacing wirings and/or sensors can cause serious damage to the wirings of the input speed sensor. If this happens, the sensor will definitely fail again.
Note that Error Code P0715 affects different makes and models of vehicles differently. Some will show noticeable symptoms, while others will keep the transmission from shifting. An automatic transmission that will not shift will not only cause inconvenience, but can pose driving safety concerns as well, which can be pretty dangerous.