Case IH 16134 – Armrest Controller or Cab Electronic System: Low pressure switch open for greater than 1 minute

The control module has detected an open circuit at the low-pressure switch for a continuous duration of over 60 seconds. An open switch typically means that the system pressure has dropped below the minimum safe operating threshold, or there is a physical break/fault in the switch or its wiring harness.

• Puma/Mid Range Magnum
• Maxxum
• Case IH Puma Series (140, 165, 180, 195, 210, 225 CVX, T6000/SWB PUMA)
• Case IH Steiger Series
• Case IH Farmall Series (40, 45, 50 CVT)

1. 1

   Enter the tractor's 'H-Menu' (Diagnostic Menu) to verify the active fault code.

2. 2

   Attach a manifold gauge set to the A/C system (or a pressure gauge to the hydraulic/transmission test port) to verify if the system is genuinely low on pressure or refrigerant.

3. 3

   Inspect the Cab Rear Left Hand wiring harness. Test the pins for the 'Low Pressure Switch Input' and 'AC-Low Pressure Switch Output' for continuity, shorts to ground, or broken wires.

4. 4

   Unplug the low-pressure switch and test it for continuity with a multimeter. If the system has proper pressure but the switch reads 'open,' the switch has failed internally.

1. 1

   Recover/Relieve Pressure

   If the system is genuinely low on pressure (e.g., an A/C refrigerant leak), locate the leak, repair the line/seal, and evacuate the system. Safety Note: Ensure all pressure is relieved from A/C or hydraulic circuits before removing valves or switches.

2. 2

   Replace the Switch

   If the wiring is intact and system pressure is normal, unscrew the faulty low-pressure switch. (Note: Many A/C low-pressure switches are mounted on a Schrader valve, meaning you can unscrew them without losing system charge, but verify your specific model's fitting first).

3. 3

   Repair Wiring

   Splice and heat-shrink any broken wires found in the Cab Rear Left Hand harness.

4. 4

   Recharge the System

   If the system was empty, recharge the A/C system with the OEM-specified weight of R134a refrigerant (or top off hydraulic fluid if it's a transmission pressure switch).

5. 5

   Clear Fault Codes

   Navigate to the 'H8' sub-system screen in the diagnostic menu to clear all stored fault codes and non-volatile memory.