Case IH 3514-04 - DEC – Engine Control Module (ECM) or Vehicle Control Module (VCM): 12 volt sensor supply instance 2 electrical circuit fault voltage below normal

The control module has detected that the 12-volt reference voltage it supplies to a specific group of sensors (Instance 2 / Supply 6) has dropped below the acceptable operating range. This is almost always caused by a short to ground in the wiring harness or an internal short circuit within one of the sensors powered by this specific circuit.

• MAGNUM AFS Connect
• Steiger
• Magnum
• Puma
• Axial-Flow combines

1. 1

   Verify the machine's battery and system voltage to ensure the ECM/VCM is receiving proper base power.

2. 2

   Identify which sensors are powered by the 'Instance 2' 12-volt circuit (often includes speed, RPM, or implement sensors).

3. 3

   Unplug the sensors on this circuit one at a time. If the voltage returns to normal (or the active fault changes to an open circuit fault), the unplugged sensor is internally shorted.

4. 4

   Inspect the wiring harness between the ECM/VCM and the sensors for chafing, pinched wires, or melted insulation causing a short to ground.

5. 5

   Inspect the ECM/VCM connector pins for corrosion, moisture ingress, or bent pins.

6. 6

   With the battery disconnected, use a multimeter to measure the resistance of the sensor supply circuit to ground to confirm the presence of a short.

1. 1

   Disconnect power

   Turn off the key switch and disconnect the machine's battery.

2. 2

   Replace faulty sensor

   If a sensor was identified as internally shorted during the diagnostic isolation step, remove it and install a replacement.

3. 3

   Repair wiring harness

   If the harness is faulty, locate the damaged section and repair the wire using OEM-approved splicing methods (soldering and heat shrink tubing) or replace the affected harness section using a wiring harness repair kit.

4. 4

   Reconnect components

   Reconnect all sensors and ensure the ECM/VCM connectors are tight and secure.

5. 5

   Restore power

   Reconnect the battery and turn the key switch to the ON position.

6. 6

   Clear fault codes

   Use the Case IH Electronic Service Tool (EST) to clear the inactive fault codes from the module.

7. 7

   Verify repair

   Start the engine and operate the machine to verify that the 3514-04 fault code does not return.