Theory Of Operation

WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

Line pressure is electronically controlled by the Transmission Control System and is measured by the Line Pressure Sensor (LPS). The desired line pressure is continuously being compared to the actual line pressure and is regulated by electronically changing the duty cycle of the Pressure Control Solenoid (PCS), (5% duty cycle = solenoid off = max line pressure, 62% duty cycle = solenoid on = minimum line pressure).

The Transmission Control System calculates the desired line pressure based on Transmission and engine inputs. A calculated torque input to the transmission is used as the primary input of the desired line pressure calculation and is called Torque Based Line Pressure. In addition, the line pressure is set to a preset level 827 to 931 kPa (120 to 135 psi) during shifts and in Park or Neutral to ensure consistent shift quality.

The P0933 can be (and often is) set in conjunction with a Gear Ratio Error or Torque Converter Clutch Out (TCC) Out of Range DTC. This could occur if slippage is detected (either within the transmission or in the TCC when engaged) while the line pressure reading is above a calibrated value.

If the P0933 is set in conjunction with other Line Pressure, Gear Ratio Error or TCC Out of Range DTC's, treat P0933 as a secondary DTC. Diagnose P0933 only if it returns after repairing the primary DTCs.