Input/Turbine Speed Sensor Circuit Malfunction
Our emissions expert has put together the following information about the P0715 fault code. We have also included diagnostic procedures you can take to your repair shop if the mechanic is having difficulty analyzing the code.
OBD II Fault Code
- OBD II P0715
Fault Code Definition
- Input/Turbine Speed Sensor Circuit Malfunction
The purpose of the automatic transmission is to match the engine's optimum power and torque characteristics to the driver's desired rate of acceleration and speed by auto-selecting different gear ratios or 'speeds' to power the wheels.
- Check Engine Light will illuminate
- Vehicle will not shift properly
- Decrease in fuel economy
- In unusual cases, there are no adverse conditions noticed by the driver
- In some cases, there may be performance problems, such as dying when coming to a stop after driving on the freeway and/or misfire-like symptoms
Common Problems That Trigger the P0715 Code
- Defective Input/Turbine Speed Sensor
- Defective Shift Solenoids
- Defective Engine Coolant Temperature Sensor
- Defective Valve Body
- Dirty transmission fluid that restricts the hydraulic passages
- Engine Misfire problem
- Internal Transmission problem
- Driveline problem
Polluting Gases Expelled
- HCs (Hydrocarbons): Unburned droplets of raw fuel that smell, affect breathing, and contribute to smog
- CO (Carbon Monoxide): Partially burned fuel that is an odorless and deadly poisonous gas
- NOX (Oxides of Nitrogen): One of the two ingredients that, when exposed to sunlight, cause smog
P0715 Diagnostic Theory for Shops and Technicians
When the code P0715 is set in the Powertrain Computer, it means that the Powertrain Computer or PCM is not seeing a speed signal from the Input/Turbine Sensor or a greater than a specified RPM difference between the rotational speed of the Input RPM Sensor and the Transmission Output RPM Sensor. This can occur during shifting or when driving at steady speeds in the same gear. It often implies that the transmission is slipping. Often times the transmission will automatically shift into a default gear and the Check Engine Light will be illuminated.
When diagnosing a P0715 code, it is important to record the freeze frame information and then to duplicate the code setting conditions with a test drive. Pay close attention to the engine load, throttle position, RPM, and road speed because a P0715 can be difficult to detect. Road test the vehicle while viewing the transmission input and output RPM PID information on a data streaming scanner. If the input RPM speed signal is unreliable or irrational then you may have verified code P0715. Be sure to verify the input speed sensor connection and wiring as well as the flex plate or flywheel teeth. If these all check out normally, then most likely you have a defective Input Speed Signal Sensor. Always use OEM parts and check for any applicable software updates.