John Deere 444.04 – BLC, HCC, RLC, DTI, VCU: Supply Voltage Too Low

Triggers when the supply voltage (BAT) to a module drops below a critical threshold (typically 9 volts). Low voltage levels usually indicate a failing battery, poor electrical connections, or charging system issues.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6M Series Tractors
• 6R Series Tractors
• 6105M
• 6125M
• MC Series Tractors
• RC Series Tractors
• 6090MC
• 6100MC
• 6110MC
• 6090RC
• 6100RC
• 6110RC
• Premium Tractors
• 6230
• 6330
• 6430
• 5M Series Tractors
• 5090M
• 5100M
• 5115M
• 770G Motor Graders
• 772G Motor Graders
• 250D Articulated Dump Trucks
• 300D Articulated Dump Trucks

1. 1

   Test the batteries to ensure they are holding a proper charge (12V+). The code triggers if voltage drops below 9V.

2. 2

   Locate the unswitched power supply wire going to the BLC (often Terminal J4) and use a multimeter to check for voltage drops between the battery and the module connector.

3. 3

   Check the ground connections for the BLC. High resistance in the ground circuit can simulate a low voltage condition at the module.

4. 4

   Inspect the wiring harness for chafing, corrosion, or pinched wires that could cause a short to ground.

5. 5

   Inspect the specific fuses and relays in the power distribution board that feed the BLC.

1. 1

   Disconnect Power

   Disconnect the negative battery terminal before servicing the electrical system.

2. 2

   Clean Connections

   Clean the battery terminals and the main chassis ground connections. Tighten them to OEM specifications.

3. 3

   Repair Wiring

   If the harness inspection revealed chafing or a short to ground on the unswitched power circuit, splice and repair the damaged wire using weather-sealed connectors, or replace the affected harness section.

4. 4

   Replace Fuses

   If a fuse feeding the BLC is blown, replace it. (Note: If it blows again immediately, you have a hard short to ground or a failed module).

5. 5

   Replace the Module

   If the battery is healthy, the wiring harness tests perfectly for continuity and lacks shorts, and the module is still reporting internal low voltage, the BLC itself has an internal fault and must be replaced.

6. 6

   Recalibrate

   If the BLC is replaced, connect John Deere Service ADVISOR to program the new module to the tractor's CAN bus network.