John Deere 000168.04 – HCC: Low Voltage to Rear Chassis Module (HCC)

The system has detected low unswitched supply voltage being supplied to a control module, such as the Rear Chassis Module (HCC). Unswitched voltage means the electrical circuit is always live, supplying power directly from the battery regardless of the ignition key's position. This is a general electrical system fault indicating that the voltage is below normal or shorted low, which may affect the proper operation of the module and the systems it controls.

• 4700
• 4720
• 5R
• 6R
• 7000
• 7010
• 7630
• 7730
• 7830
• 7930
• 7R
• 8245R
• 8270R
• 8295R
• 8R
• 9230
• 9330
• 9430
• 9470RX
• 9520R
• 9520RT
• 9520RX
• 9530
• 9570R
• 9570RT
• 9570RX
• 9620R
• 9620RX
• 9630
• 9R
• R4038

1. 1

   Reduce the electrical load on the machine and increase the engine RPM to see if the voltage recovers and the code clears

2. 2

   Visually inspect the area around the batteries and alternator for any signs of damage, corrosion, or accumulated debris

3. 3

   Ensure all connections, including battery terminals and ground straps, are clean and tight

4. 4

   Test battery voltage with the engine off using a multimeter (a fully charged battery should read approximately 12.6 volts)

5. 5

   Test alternator voltage with the engine running at around 1500 RPM (a properly functioning charging system should read between 13.5 and 14.5 volts)

6. 6

   Inspect fuses related to the affected control unit (e.g., F102 10-amp fuse for SR1, or F30 for SCU)

1. 1

   Identify the faulting controller

   Use the machine's display to confirm exactly which controller is logging the 000168.04 code, as it can be triggered by various modules.

2. 2

   Consult wiring schematic

   Using Service ADVISOR or a technical manual, locate the wiring diagram specific to the identified controller and your machine's serial number.

3. 3

   Trace the unswitched power circuit

   Follow the unswitched power wire from the battery, through any relevant fuses and connectors, directly to the control module.

4. 4

   Test for voltage drops

   With the circuit live, use a multimeter to check for voltage at various points along the circuit to pinpoint where the voltage drop is occurring. Look for corroded wires, faulty connectors, or a failing fuse holder.

5. 5

   Repair or replace damaged components

   Repair or replace any damaged wiring or connectors found during testing. If a fuse is blown, replace it and investigate the cause of the overcurrent before resuming operation.

6. 6

   Replace the control module

   If the wiring and charging system are confirmed to be in good condition and the voltage drop is internal, the control module itself may be faulty and require replacement.