John Deere 000158.04 – RLC, OIC, HCU, SCU, AIC, PTQ: Voltage To Cab Roof Module (RLC) Below 9 Volts

The switched power supply to a specific control module has dropped below 9.0 volts. This low voltage condition occurs in a circuit that is active only when the vehicle's ignition key is in the ON or RUN position, and it can impair or completely disable the proper operation of the affected controller.

• 6R Series
• 6110R
• 6120R
• 6130R
• 7R Series
• 8R Series
• 9R Series
• 7200R
• 8225R
• 9230
• 9330
• 9430
• 9530
• 9630
• RT models
• RX models
• 7020 Series
• 7720
• 7820
• 7920
• 8030 Series
• 8130
• 8230
• 8330
• 8430
• 8530
• 210K
• 317G
• 333E

1. 1

   Restart the vehicle by cycling the key switch off and on, as this can sometimes clear the code

2. 2

   Reduce electrical load by turning off non-essential components (like extra lights) and increasing engine RPM to see if the voltage drop is temporary

3. 3

   Visually inspect the area around the batteries and alternator for damage, loose connections, accumulated debris, or corrosion on terminals

4. 4

   Check system fuses for blown circuits (e.g., F15 for CAB switched power, F30 for HCU/SCU, or F24, F44, and F51 for 7020 series SCU)

5. 5

   Check overall system voltage to determine if the battery is defective or if the alternator is failing to charge correctly

1. 1

   Isolate the reporting module

   Access the diagnostic trouble codes through the machine's display (e.g., CommandCenter) to confirm exactly which control module (RLC, OIC, HCU, SCU, etc.) is logging the 000158.04 fault.

2. 2

   Perform circuit tests

   Using a multimeter and the machine's technical manual for wiring diagrams, test the power supply and ground circuits for the specific control unit logging the code to verify voltage specifications.

3. 3

   Check for intermittent wiring issues

   Attempt to replicate the conditions under which the fault occurs. Wiggle wires and connectors in the relevant harness to reveal any loose connections or broken wires.

4. 4

   Consult a dealer or replace module

   If the wiring and power supply are verified good but the fault persists, the control module itself may be faulty. Contact an authorized John Deere dealer for advanced diagnostics or module replacement.