Pressure Switches
WARNING: This page is about a different car, the 2015 RAM 3500 HD and 2015 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The TCM relies on five pressure switches to monitor fluid pressure in the L/R, 2C, 4C, UD, and OD hydraulic circuits. The primary purpose of these switches is to help the TCM detect when clutch circuit hydraulic failures occur. The switches close at 23 psi and open at 11 psi, and simply indicate whether or not pressure exists. The switches are continuously monitored by the TCM for the correct states (open or closed) in each gear as shown in the following charts.
66RFE PRESSURE SWITCH STATES
| GEAR | ERS DISPLAY | L/R | 2C | 4C | UD | OD |
| R | OP | OP | OP | OP | OP | |
| P/N | CL | OP | OP | OP | OP | |
| 1ST | 1 | CL* | OP | OP | CL | OP |
| 2ND | 2 | OP | CL | OP | CL | OP |
| 3RD | 3 | OP | OP | CL | CL | OP |
| 4TH | 4 | OP | OP | OP | CL | CL |
| 5TH | 5 | OP | OP | CL | OP | CL |
| 6TH | 6 | OP | CL | OP | CL | CL |
| *L/R is closed if output speed is below 100 RPM in Drive. L/R is always closed in ERS1. |
A Diagnostic Trouble Code (DTC) will set if the TCM senses any switch open or closed at the wrong time in a given gear.