How to fix P0731 Code: Gear 1 Incorrect Ratio
A P0731 code is set when the computer (TCM/PCM) detects that the revolutions per minute (RPM) difference between the rotational speed of the two sensors in Gear 1 falls outside the normal range.
Common causes for the P0731 code include a defective gear 1 shift solenoid, internal transmission failure, and a bad speed sensor.
Possible Causes of a P0730 Code:
Low Fluid - Dirty Fluid - Clogged Filter
Bad Transmission Sensor (Input - Output Speed Sensors)
Transmission Failure (Pump, Planetary Gear, Solenoid)
Wiring Harness or Bad Computer (TCM/PCM)
By using this information user assumes all risk of use.