John Deere 000158.03 – Rear Chassis Module: Switched Supply Voltage High

The system has detected a voltage level to a control module that exceeds 16 volts. This overvoltage condition is typically caused by a charging system fault and can potentially damage sensitive electronic components if left unaddressed.

• 9230
• 9330
• 9430
• 9530
• 9630
• 8120
• 8220
• 9520
• 9620
• 8130
• 8230
• 8330
• 8430
• 8530
• 6R
• 7R
• 8R
• 9R

1. 1

   Turn the ignition key off, wait a moment, and turn it back on to see if the code clears (checking for an intermittent issue)

2. 2

   Visually inspect the alternator and battery terminals for any signs of damage, corrosion, or loose connections

3. 3

   With the engine running, use a multimeter to measure the voltage at the battery and at the alternator's output stud (normal is typically 13.5-14.8V for a 12V system)

4. 4

   Inspect fuses related to the affected controller (e.g., SCC, HCU)

5. 5

   Examine the wiring harness leading to the controller logging the code for damage, chafing, or short circuits from another higher-voltage wire

6. 6

   Determine if the high voltage condition is present across the entire machine (points to alternator) or only detected at the input pin of a single controller (points to wiring short or internal controller failure)

1. 1

   Confirm the fault

   After performing initial diagnostic checks, confirm that the fault code is active and not just a stored, historical event.

2. 2

   Replace alternator

   If diagnostic checks reveal a system-wide overcharging condition (voltage significantly above 14.8V), the alternator/voltage regulator assembly is the most likely cause and must be replaced.

3. 3

   Repair wiring

   If a wiring fault is identified, repair the damaged section of the harness. Ensure all connections are clean, secure, and properly insulated. Resolve any short circuits between power wires.

4. 4

   Replace control module

   If the system voltage is normal and the wiring to the module is intact, verify that the module is receiving the correct voltage inputs at its connector pins. If inputs are correct but the code remains, replace the control module that is logging the fault.