Case IH 151 – Transmission Controller (TRANS): Front suspension pressure sensor rod side open circuit

The controller is not receiving a valid voltage signal from the pressure sensor monitoring the rod side of the front suspension hydraulic cylinders, typically due to a broken wire, disconnected plug, or an internally failed sensor.

• MX Magnum
• Magnum 225
• Magnum 250
• Magnum 275
• Magnum 305
• Magnum 310
• Magnum 340
• Puma 170
• Puma 180
• Puma 195
• Puma 210
• Puma 260

1. 1

   Locate the front suspension level control block (on Puma models, this is often located on top of the rear axle housing; on Magnum models, it is typically located near the front axle or left-hand side). Inspect the wiring harness and connector going to the rod side pressure sensor for breaks, corrosion, or loose pins.

2. 2

   Use the Case IH Electronic Service Tool (EST) or the tractor's A-post display to view the 'Trans FSUS' pressure page. Check the rod side pressure reading. If it reads an abnormal default value (like 0 psi or a fixed out-of-range value) while the piston side reads normally, the sensor or its circuit is confirmed faulty.

3. 3

   Disconnect the sensor and check for proper reference voltage and ground at the harness connector. If power and ground are present, the sensor itself has failed open.

1. 1

   Depressurize the System

   Before removing any hydraulic components, the system must be completely depressurized. Lower the front axle manually. Locate the adjusting/release screws on the suspension solenoid valve block. Turn the manual release screws to bleed the pressurized oil back to the tank. Both the piston side and rod side must be depressurized individually.

2. 2

   Locate the Sensor

   Identify the rod side pressure sensor on the level control block.

3. 3

   Remove the Sensor

   Disconnect the electrical connector from the sensor. Carefully unscrew the faulty pressure sensor from the block.

4. 4

   Install the New Sensor

   Lubricate the new O-ring with clean hydraulic oil and install it on the new sensor. Thread the new sensor into the block and tighten it to the manufacturer's specification.

5. 5

   Reconnect

   Plug the electrical connector back into the new sensor.

6. 6

   Restore System

   Close the manual pressure release screws on the valve block.

7. 7

   Calibrate

   Start the tractor. Use the EST or onboard display to clear the TRANS 151 fault code. You may need to run the front suspension calibration routine to ensure the system levels correctly.