Case IH 518847-04 - VCM – VCM: VCM 12VF1 Supply Voltage Low

Fault code 518847-04 indicates that the Vehicle Control Module (VCM) has detected the voltage supplied to the 12VF1 power rail is below the normal operational limit. This circuit provides power to specific auxiliary functions such as auxiliary retract inputs, bucket extend, boom raise/lower, or implement controls. In almost all cases, this condition is caused by a blown fuse protecting the 12VF1 circuit, which cuts off power to these auxiliary systems.

• MAGNUM AFS Connect
• Magnum AFS Connect Series
• Magnum 400
• Steiger AFS Connect Series
• Axial-Flow Combines
• Axial-Flow 7250
• Case IH Skid Steer Loaders (SSL)
• Case IH Compact Track Loaders (CTL)

1. 1

   Check the 12VF1 Fuse (F-012, 5 Amp) in the main fuse panel

2. 2

   Inspect the wiring harness between the fuse panel, the VCM, and the auxiliary solenoids for chafing, pinched wires, or shorts to ground

3. 3

   Verify system voltage at the battery and main power relays to ensure adequate overall voltage is supplied to the VCM

4. 4

   Perform a pin-out test by disconnecting the VCM connector and measuring voltage at the 12VF1 input pin with the key on to rule out internal VCM faults

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the battery ground cable to ensure safety.

2. 2

   Locate the Fuse

   Access the main vehicle fuse panel and locate the fuse designated for the VCM 12VF1 circuit (commonly F-012).

3. 3

   Test the Circuit

   Remove the fuse. Using a digital multimeter, check the load side of the fuse terminal for continuity to ground. If continuity exists, trace the harness to locate and repair the short circuit.

4. 4

   Repair Wiring

   Splice and heat-shrink any damaged wiring in the harness leading to the VCM or auxiliary solenoids if a short was found.

5. 5

   Replace the Fuse

   Install a new 5 Amp fuse into the slot. Never install a fuse with a higher amperage rating than specified.

6. 6

   Reassemble and Clear Codes

   Reconnect the battery ground, power on the machine, and use the diagnostic display or an Electronic Service Tool to clear the inactive fault codes.

7. 7

   Operational Test

   Actuate the auxiliary hydraulic functions (boom, bucket, or remote valves) to ensure the circuit holds the load and the fault code does not return.