Case IH 1547-03 - BCM – Cab Controller / Body Control Module (BCM): A/C Evaporator Temperature Sensor - Voltage too high / Out of range high

The system is detecting a sensor voltage greater than 4.47 VDC, indicating that the sensor's electrical resistance has exceeded 101K Ohms. This typically points to an open circuit, a disconnected plug, or a completely failed sensor.

• MAGNUM AFS Connect
• 2144
• 2166
• 2188
• 2344
• 2366
• 2377
• 2388
• 2577
• 2588
• 5088
• 6088
• 7088
• 7010
• 8010
• 2155
• 2555
• CPX420
• CPX610
• CPX620
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340

1. 1

   Visually inspect the evaporator temperature sensor connector near the HVAC box for unplugged connectors, broken wires, or rodent damage.

2. 2

   Perform a resistance test on the disconnected sensor using a multimeter. If resistance reads extremely high (>101K Ohms) or shows an open circuit (OL) at normal ambient temperatures, the sensor has failed internally.

3. 3

   Perform a voltage test on the harness side of the connector with the key ON. If the 5V reference voltage is present but the code persists when plugged in, the sensor is faulty. If voltage is missing or shorted to battery voltage, there is a wiring harness issue.

1. 1

   Access the HVAC Unit

   Gain access to the cab's HVAC evaporator box. On many Case IH combines, this requires removing the access panels behind or under the operator seat.

2. 2

   Locate the Sensor

   Find the evaporator temperature sensor, which features a long metal probe inserted directly into the aluminum fins of the A/C evaporator core.

3. 3

   Disconnect

   Unplug the electrical pigtail connector for the sensor.

4. 4

   Remove the Old Sensor

   Carefully pull the sensor probe straight out of the evaporator fins. Do not bend or damage the delicate fins of the evaporator core.

5. 5

   Install the New Sensor

   Gently insert the new sensor probe into the exact same location in the evaporator core. Ensure it is seated to the proper depth so it accurately reads the core temperature to prevent freezing.

6. 6

   Reconnect and Test

   Plug in the electrical connector. Turn the machine's key to the ON position, clear the inactive 1547-03 fault code from the display, and run the A/C to verify proper operation.