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:

Once in a particular gear, if the gear ratio varies from the correct gear ratio, the corresponding in-gear DTCs P0731-36 and P1736 is set.
An excessive change in input or output speeds indicating an intermittent signal which results in DTCs P0716 and/or P0721 setting.
If the common speed sensor ground circuit is lost, both sensor inputs will read the pulses from the input speed sensor when at a stop in neutral. Since the input speed sensor reads 60 teeth from the input clutch hub and the output speed sensor reads 30 teeth from the park gear, the result is an apparent speed ratio of 1:2 and may cause DTC P1794 to set.

NOTE:

Various Gear Ratio Error DTCs will set only if the transmission slips after first achieving the correct ratio. Therefore, a transmission with no DRIVE (or REVERSE) may not set any Gear Ratio Error DTCs because it never achieved a correct gear ratio.