Case IH 520596-03 - BCM – BCM: ATC cab air temperature sensor - out of range - high

An 'out of range - high' condition on a temperature sensor circuit typically means the signal voltage is too high (often reading near or above 4.8 VDC). This high voltage indicates that the sensor's resistance is extremely high (e.g., greater than 60K Ohms), which the system interprets as an impossibly cold temperature. This is almost always caused by an open circuit, a completely disconnected sensor, or a short to a higher voltage source.

• MAGNUM AFS Connect
• Magnum 400 AFS Connect

1. 1

   Locate the cab air temperature sensor and inspect its wiring harness. An unplugged or loose connector will immediately cause an open circuit and trigger this code.

2. 2

   Inspect the sensor's signal wire for any signs of an open circuit (broken wire) or a short to a higher voltage source.

3. 3

   Measure the resistance of the cab air temperature sensor. If the multimeter shows an open circuit or extremely high resistance at normal ambient temperatures, the sensor has failed internally.

1. 1

   Access HVAC components

   Access the HVAC / ATC components inside the cab. Depending on the exact cab configuration, you may need to remove storage boxes or interior cab covers to reach the sensor.

2. 2

   Disconnect harness

   Disconnect the harness assembly from the faulty cab air temperature sensor.

3. 3

   Inspect connector

   Inspect the harness connector pins for corrosion, moisture, or pushed-out pins. Clean or repair the connector if necessary.

4. 4

   Remove sensor

   Remove the defective cab air temperature sensor from its mounting location.

5. 5

   Install new sensor

   Install the new cab air temperature sensor.

6. 6

   Reconnect harness

   Reconnect the harness assembly securely to the new sensor.

7. 7

   Reassemble cab interior

   Reinstall any storage boxes or cab covers that were removed during disassembly.

8. 8

   Clear codes and verify

   Turn on the machine, clear the BCM fault codes via the AFS Connect display, and verify that the ATC system resumes normal automatic climate control operation.