Case IH 16129 – ATC (Automatic Temperature Control): High pressure cycling error (2 in 1 minute)

The Air Conditioning (A/C) high-pressure cutout safety switch has tripped (opened) twice within a 60-second window. This indicates dangerous pressure spikes in the A/C refrigerant lines. The switch instantly interrupts the compressor clutch power circuit to prevent catastrophic system blowouts or hose ruptures, causing the A/C clutch to not kick in and the cab to lose cooling.

• Puma/Mid Range Magnum
• Maxxum
• Case IH Puma Series (115, 125, 140, 150, 155, 165, 180, 195, 210, 225, 240)
• Case IH Magnum Series (180, 215, 235, 245, 275, 305, 340 Series 4)
• Case IH Steiger Series (330, 380, 435, 485, Quadtrac)
• Case IH Maxxum Series (110, 115, 125, 140)

1. 1

   Inspect the A/C condenser and radiator fins for dust, chaff, or debris restricting airflow

2. 2

   Verify the engine cooling fan or viscous fan clutch is engaging properly

3. 3

   Connect A/C manifold gauges to verify system pressures and check for an overcharged system

4. 4

   Test the high-pressure switch for continuity (normally closed, opens around 390 PSI)

5. 5

   Inspect the receiver drier and expansion valve for blockages causing liquid line pressure spikes

1. 1

   Cool down machine

   Turn off the tractor and allow the engine and cooling stack to cool down.

2. 2

   Clean condenser and radiator

   Thoroughly clean the A/C condenser and radiator fins using compressed air or a pressure washer to ensure maximum airflow. If the code was caused by poor airflow, clearing the code after cleaning may resolve the issue.

3. 3

   Locate high-pressure switch

   If the switch itself is faulty, locate the A/C high-pressure switch. It is typically positioned directly onto the high-pressure liquid refrigerant line or the receiver drier canister block.

4. 4

   Disconnect harness

   Disconnect the electrical pigtail/harness from the switch.

5. 5

   Recover refrigerant

   Recover the A/C refrigerant using an approved A/C recovery machine (Note: some CNH systems feature a Schrader valve under the switch allowing it to be unscrewed without discharging the system, but verifying the system charge weight is recommended if pressure issues are present).

6. 6

   Remove faulty switch

   Unscrew the faulty high-pressure switch from the fitting.

7. 7

   Install new switch

   Thread the new OEM high-pressure switch onto the fitting and tighten securely.

8. 8

   Reconnect harness

   Reconnect the electrical harness to the switch.

9. 9

   Evacuate and recharge A/C

   Evacuate the A/C system and recharge it with the exact OEM-specified weight of refrigerant.

10. 10

    Clear code and verify

    Use the tractor's diagnostic display or service tool to clear the ATC 16129 fault code, start the tractor, and verify that the A/C compressor clutch engages properly without short-cycling.