Case IH 518507-04 - BCM – BCM: A/C compressor high pressure sensor signal out of range

The control module is receiving an electrical signal (voltage) that falls outside the normal operating parameters of the sensor, indicating an electrical circuit fault (such as a short, open wire, or failed sensor) rather than a simple mechanical refrigerant pressure issue.

• MAGNUM AFS Connect
• Magnum AFS Connect series
• Magnum 400 AFS Connect
• Puma series
• Puma 200
• Puma 215
• Puma 230

1. 1

   Inspect the wiring harness and connectors, particularly where the main engine harness connects, for bad connections that can trigger false high-pressure codes.

2. 2

   Test the circuit by verifying if the component is a normally-closed switch or a variable sensor. Bypassing a normally closed switch by jumpering the connectors can temporarily test the circuit, but may trigger other codes (like 129) if left running.

1. 1

   Locate sensor

   Locate the A/C high pressure sensor/switch. It is typically threaded into the high-pressure liquid line or near the receiver drier.

2. 2

   Disconnect harness

   Disconnect the electrical connector from the sensor.

3. 3

   Remove sensor

   Remove the sensor from the A/C line. Verify if it is mounted on a Schrader valve before removal to prevent venting refrigerant.

4. 4

   Install new sensor

   Install the new sensor/switch. Note that some Case high-pressure switches use an M10 x 1.25 thread size.

5. 5

   Reconnect harness

   Reconnect the electrical harness to the new sensor.

6. 6

   Clear codes and test

   Clear the BCM fault codes and test the A/C system for proper operation.