John Deere 5125.03 – ECU: Sensor Supply Voltage 7 Out of Range High

The 5-volt reference circuit (Sensor Supply 7) is experiencing a voltage higher than its upper limit, which typically means the circuit is shorted to a 12-volt power source.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5090M
• 5100M
• 5100MH
• 5100ML
• 5115M
• 5085M
• 5095M
• 5105M
• 5115ML
• 8235R
• 8245R
• 8260R
• 8285R
• 8310R
• 8335R
• 8360R
• 8400R

1. 1

   Inspect the engine wiring harness associated with Sensor Supply 7 (routing to MAP, Crankcase Pressure, and EGR Flow Meter sensors) for damaged, frayed, or melted wires shorting to 12V.

2. 2

   Perform a sensor isolation test by disconnecting the sensors on this circuit one at a time. If voltage returns to normal or the code changes to 005125.04 (Low), the disconnected sensor is internally shorted.

3. 3

   Test the ECU output directly. If all sensors are disconnected and the harness is isolated but the ECU pin still reads 12V, the ECU may have an internal short.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical spikes during repair.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a short in the harness, repair the damaged section of the wire using OEM-approved splices and heat-shrink tubing, or replace the affected harness pigtail.

3. 3

   Replace Faulty Sensor

   If a sensor was found to be internally shorted to 12V, remove the mounting hardware, unplug the electrical connector, and install the replacement sensor.

4. 4

   Reassembly

   Reconnect all sensor connectors and restore battery power.

5. 5

   Reset and Verify

   Use a John Deere diagnostic tool (Service ADVISOR) to clear the ECU fault codes. Start the engine and monitor the system to ensure the 005125.03 code does not return and that the sensor supply voltage remains at a steady 5 volts.