John Deere 3514.04 – Engine Control Unit (ECU): Sensor Supply Voltage 6 Out of Range Low

The Engine Control Unit (ECU) provides a 5-volt reference signal (Sensor Supply #6) to a specific group of sensors. This code indicates that the voltage on this circuit has dropped below the acceptable threshold. This is almost always caused by a short to ground somewhere in the circuit, either within the wiring harness or internally within one of the sensors on that 5V loop.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5090M
• 5100M
• 5100MH
• 5100ML
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6090MC
• 6150R
• 6210R
• 7200R
• 7215R
• 7230R
• 8245R
• 8310R
• 8360RT
• 9470RT
• 9520RT
• 9570RT
• S650
• S660
• S670
• S760
• S770
• 8000 Series Forage Harvesters
• 9000 Series Forage Harvesters
• 524K
• 544K
• 710K
• 744K
• 850K
• 250D
• 300D

1. 1

   Turn the key ON (engine OFF) and use a multimeter to measure the voltage at the 5V supply pin of one of the affected sensors (EGR Valve Position, Exhaust Manifold Pressure, or Coolant Pressure). It will likely read near 0V.

2. 2

   Disconnect the EGR Valve Position Sensor, Exhaust Manifold Pressure Sensor, and Coolant Pressure Sensor one at a time.

3. 3

   Monitor the 5V reference voltage. If it immediately returns to normal (approx. 5.0V) upon unplugging a specific sensor, that sensor has an internal short and must be replaced.

4. 4

   If all sensors on the #6 supply circuit are unplugged and the voltage is still low, the short to ground is in the wiring harness. Inspect the harness for chafing, melted insulation, or rubbing against the engine block or frame.

5. 5

   Inspect all related sensor connectors and the ECU pins for water intrusion, corrosion, or bent pins that could be bridging the 5V supply to a ground wire.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery terminal before repairing wiring or replacing sensors.

2. 2

   Replace the Faulty Component

   If a sensor was identified as internally shorted during the isolation test, remove and replace it. If the wiring harness is damaged, locate the shorted section. Splice and solder a new section of wire, sealing it with heat-shrink tubing, or replace the affected harness pigtail.

3. 3

   Reassemble and Reconnect

   Plug all sensors back in and reconnect the battery.

4. 4

   Clear Codes and Test

   Turn the key ON and use a diagnostic scan tool to clear the 003514.04 fault code. Start the engine and monitor the live data for the EGR position, exhaust manifold pressure, and coolant pressure to ensure they are reading accurately and the code does not return.