John Deere 3512.03 – ECU: Sensor Supply #4 Voltage Out of Range High

The controller has detected that the 5-volt reference supply circuit #4 is operating above its specified voltage range (typically above 5.2V for more than 2 seconds). This condition almost always indicates that the 5-volt supply wire is shorted to a higher voltage source, such as a 12-volt battery line.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5090M
• 5115M
• 331G
• 333G
• 7R Series
• 8R Series
• 8245R
• 8400R
• 9RT Track Tractors
• 9470RT
• 9520RT
• 9570RT
• 8430
• 310G
• 310J
• 410G
• 710G
• 4930
• 4940
• 750J-II
• 850J
• 330LC-8B
• 7180
• 7280
• 7380
• 310SG
• 315SG
• 210LE
• 7200R
• 8345RT

1. 1

   Consult the specific machine's electrical schematic to identify exactly which sensors share the ECU Sensor Supply #4 circuit.

2. 2

   Perform a sensor isolation test: Turn the key ON (engine OFF) and disconnect the sensors on the #4 supply circuit one at a time (e.g., unplug the Foot Throttle Position Sensor).

3. 3

   Monitor the code: If the 003512.03 code goes inactive (or flips to a 003512.04 'Voltage Low' code) when a specific sensor is unplugged, that sensor has an internal short to voltage and is the culprit.

4. 4

   If all sensors on the circuit are unplugged and the code remains active, the short to 12V is in the wiring harness. Use a multimeter to check for continuity between the 5V supply wire and any 12V power sources.

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery cable to prevent accidental shorts during repair.

2. 2

   Inspect Harness

   Trace the wiring harness from the ECU to the sensors on the #4 circuit. Look for areas where the wire loom is rubbed through, pinched, or melted against the engine block or chassis, causing the 5V wire to touch a 12V wire.

3. 3

   Repair Wiring

   If a harness short is found, cut out the damaged section of wiring, solder in a new section of wire, and seal it with heat-shrink tubing. Reroute the harness away from abrasion points.

4. 4

   Replace Sensor

   If the isolation test proved the Foot Throttle Position Sensor was internally shorted, unbolt the faulty sensor from the pedal assembly, install the new sensor, and plug in the connector.

5. 5

   Calibrate

   Some machines require a throttle pedal calibration via the monitor or John Deere Service ADVISOR after replacing a position sensor.

6. 6

   Clear Codes

   Reconnect the battery, turn the key ON, and clear the stored ECU codes. Test machine operation to ensure the code does not return.