Theory Of Operation
WARNING: This page is about a different car, the 2015 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.
The transmission system uses two speed sensors, one to measure input shaft speed and one to measure output shaft speed. These inputs are essential for proper transmission operation. Therefore, the integrity of this data is verified through the following checks:
- When in gear, if the gear ratio does not match a known gear ratio, the corresponding in-gear DTCs P0731-36, P1736, and P1776 is set.
- An excessive change in input or output speeds indicating an intermittent signal results in DTCs P0716 and or P0721 setting.
- If the common speed sensor ground circuit is lost, both sensor inputs will read the signal from the input speed sensor at idle in neutral. Since the input speed sensor has 60 teeth and the output speed sensor has 30 teeth, this results in a an apparent speed ratio of 1:2 and may cause DTC P1794 to set.