Theory Of Operation
WARNING: This page is about a different car, the 2016 RAM 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The purpose of the diagnostic is to check if the turbine speed sensor signal is rational by monitoring for either a missing or invalid speed sensor pulse. The turbine speed sensor is a Hall-Effect sensor with an output range that alternates between normal high and normal low voltages as the turbine tone wheel rotates. The following rationality checks are performed continuously by the TCM:
- Output Speed Comparison: If the number of turbine speed sensor pulses is equal to zero while the output speed sensor signal is greater than or equal to a calibrated value, a DTC will be set.
- Wheel Speed Comparison: If the number of turbine speed sensor pulses is equal to zero while the wheel speed based calculated output shaft speed value is greater than or equal to a calibrated value, a DTC will be set.
- Maximum Negative Gradient: If the turbine speed sensor signal decelerates at a rate greater than a calibrated value, a DTC will be set.