A transmission code is a Diagnostic Trouble Code (DTC) stored by the vehicle’s computer when it detects a fault in the transmission, transmission control module, sensors, solenoids, or related electrical circuits.
Most transmission-related OBD-II codes begin with P07, although some vehicles may also use manufacturer-specific transmission codes. Common examples include:
P0700 – Transmission Control System Malfunction
P0715 – Input/Turbine Speed Sensor Circuit Malfunction
P0720 – Output Speed Sensor Circuit Malfunction
P0730 – Incorrect Gear Ratio
P0740 – Torque Converter Clutch Circuit Malfunction
P0750 – Shift Solenoid A Malfunction
P0755 – Shift Solenoid B Malfunction
P0760 – Shift Solenoid C Malfunction
P0770 – Shift Solenoid E Malfunction
These codes can be caused by low or dirty transmission fluid, faulty speed sensors, damaged wiring, bad shift solenoids, valve body problems, torque converter issues, or internal transmission wear.
There is no single code that automatically means the transmission is bad. For example, P0700 only indicates that the transmission control system has detected a problem and usually requires a more advanced scan tool to read the specific transmission module codes.
If the vehicle has symptoms such as hard shifting, slipping, delayed engagement, getting stuck in one gear, transmission overheating, or limp mode, scan it with an OBD-II diagnostic tool first. The stored code, transmission fluid condition, live sensor data, and driving symptoms should all be checked before replacing the transmission.