Case IH 1915 – VCM: VCM - Rail 12VT1 - Two Speed Input Power Off

The controller has detected a loss of power, an open circuit, or a short on the specific internal 12-volt power rail (12VT1) that supplies voltage to the two-speed travel input circuit. The system disables the two-speed function as a failsafe.

• skid steer
• SR130
• SR150
• SR175
• SR200
• SR210
• SR240
• SR250
• SR270
• SV185
• SV250
• SV280
• SV300
• SV340
• TR270
• TR310
• TR320
• TR340
• TV380
• TV450

1. 1

   Check the main fuse box for any blown fuses or tripped relays related to the VCM/UCM power supply and the two-speed/auxiliary hydraulic circuits.

2. 2

   Inspect the wiring harness running from the VCM to the two-speed selector switch (usually located on the joystick) and down to the two-speed drive motor solenoids. Look for chafing, cuts, or corrosion, which are common in the lower chassis of skid steers.

3. 3

   Test the two-speed trigger/switch on the joystick for proper continuity when toggled.

4. 4

   Unplug the two-speed solenoid at the drive motor and check the coil resistance with a multimeter to ensure it is not shorted to ground or internally open.

5. 5

   Measure the voltage at the VCM connector for the 12VT1 rail to determine if power is reaching the module, or if the module is failing to output power to the circuit.

1. 1

   Safely Prep the Machine

   Park the machine on a level surface, lower the loader arms (or engage the cylinder lock), turn off the engine, and disconnect the negative battery cable.

2. 2

   Check Power Distribution

   Locate the cab fuse panel. Test and replace any blown fuses related to the VCM or travel controls. If a fuse is blown, do not just replace it—trace the circuit for a short to ground.

3. 3

   Inspect and Clean Connectors

   Disconnect the harness at the two-speed solenoid(s) on the hydrostatic drive motors. Inspect the pins for moisture, dirt, or corrosion. Clean thoroughly with electrical contact cleaner and apply dielectric grease.

4. 4

   Repair Harness Damage

   Trace the wiring harness from the drive motors back to the VCM. If any wires are pinched or bare (especially where the harness routes near moving loader arms or the cab tilt pivot), cut out the damaged section and repair it using weather-sealed, heat-shrink butt connectors.

5. 5

   Test the Component

   Reconnect the battery. Turn the key to the ON position and toggle the two-speed switch. Listen for the solenoid "click."

6. 6

   Module Replacement (If Necessary)

   If the wiring, switch, and solenoids all test perfectly fine but the 12VT1 rail still has no power, the VCM/UCM has suffered an internal hardware failure. The module must be replaced. Note: A new VCM requires dealer programming (EST diagnostic tool) to flash the correct machine software and self-learning parameters.