Case IH 1902 – VCM: VCM - VCM Supply Voltage Low

The input power supply voltage reaching the module has dropped below the acceptable operational threshold.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• TR270
• TV380
• SR/SV series

1. 1

   Verify that the machine's battery is fully charged (resting above 12.4V) and that the alternator is maintaining proper voltage under load. Low system voltage will trigger this code.

2. 2

   Locate the power distribution box and test the fuses and relays responsible for supplying power to the VCM.

3. 3

   Inspect the wiring harness leading to the VCM. Look for chafed wires, pinched harnesses, or corrosion inside the VCM connectors.

4. 4

   Back-probe the power and ground pins at the VCM connector while the circuit is loaded to check for excessive voltage drop, which indicates high resistance in the wiring or a bad ground connection.

1. 1

   Disconnect Power

   Always disconnect the negative battery cable before servicing the electrical system.

2. 2

   Repair Wiring/Connections

   If the diagnostic checks revealed corroded pins or damaged wires, clean the connectors with electrical contact cleaner and repair any broken wire segments using weather-sealed splice connectors.

3. 3

   Replace Fuses/Relays

   If a relay is sticking or a fuse is blown, replace it with an OEM equivalent.

4. 4

   Replace the VCM

   If the wiring, grounds, and supply voltage at the connector are all within specification but the VCM still registers a low voltage internal fault, the VCM itself has failed. Remove the mounting hardware, disconnect the harness, and install the new VCM.

5. 5

   Reprogramming

   If a new VCM/UCM is installed, you must use the Case IH Electronic Service Tool (EST) to configure the module to the specific machine and restore self-learning parameters.

6. 6

   Clear Codes

   Reconnect the battery, turn the key on, and use the EST or diagnostic scanner to clear the 1902 fault code.