John Deere 3509.03 – CCU, ECU, PTR, AIC, or ECM: 5-Volt Sensor Supply Circuit Voltage Too High

A control module has detected that the 5-volt sensor supply circuit is outputting a voltage higher than the normal operating range (typically above 5.2 to 5.25 volts) for longer than 2 seconds.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5045E
• 5055E
• 5065E
• 5075E
• 5065M
• 5075M
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5095M
• 5095MH
• 5105M
• 5015ML
• 5090M
• 5115M
• 6100D
• 6110D
• 6115D
• 6125D
• 6130D
• 6140D
• 9470RT
• 9520RT
• 9570RT

1. 1

   Monitor Sensor Voltage: Use the machine's diagnostic display or a multimeter to check the actual voltage on the 5V reference circuit. Confirm it is reading above 5.2V.

2. 2

   Inspect Wiring and Connections: Visually inspect the wiring harnesses and connectors related to the 5V sensor supply. Look for rubbed-through wire insulation that could be causing a short to a 12V battery source.

3. 3

   Isolate the Sensors: Disconnect the sensors on this circuit one at a time. If the voltage drops back to a normal 5V when a specific sensor is unplugged, that sensor is shorted internally.

4. 4

   Test the Control Module Output: If all sensors are unplugged and the wiring harness tests good (no shorts to 12V), test the 5V output pin directly at the control module (CCU/ECU). If the module itself is outputting more than 5.2V, its internal voltage regulator has failed.

1. 1

   Disconnect Battery

   Before repairing wiring or replacing modules, disconnect the negative battery terminal.

2. 2

   Repair Wiring

   If a short to a 12V source was found in the harness, repair the damaged wires using OEM-approved splicing methods and heat shrink, then re-loom the harness.

3. 3

   Replace Faulty Sensor

   If unplugging a sensor resolved the overvoltage, replace that specific sensor. Clean the connector with electrical contact cleaner before installing the new sensor.

4. 4

   Replace the Control Module

   If the module's internal regulator failed, remove the faulty CCU/ECU. Install the new module. Note: A new control module will require programming/calibration by a John Deere dealer using Service ADVISOR software to flash the correct machine configuration data.

5. 5

   Clear Codes and Test

   Reconnect the battery, turn the key on, and clear the stored diagnostic trouble codes. Run the machine and verify that the 5V circuit remains stable and code 003509.03 does not return.