New Holland ENG 3284 – Engine Control Module (ECM) / Bosch EDC7: Sensor Supply Voltage 2 - Low

This code indicates that the 5-volt reference circuit #2 has dropped below its acceptable operating threshold. When 'Supply 2' drops low, it almost always means the circuit is shorted to ground, either due to a chafed wiring harness or an internally shorted sensor pulling the voltage down.

• T7.220
• T7.235
• T7.250
• T7.260
• T7.270
• T8 Series
• B110B
• LB110
• B115
• L180
• W170B
• W190B
• CR9090
• CX8080
• CX8090

1. 1

   Check battery voltage to ensure sufficient system voltage, as low voltage can trigger false supply codes.

2. 2

   Perform a sensor disconnect test by unplugging sensors on the Supply 2 circuit one at a time to see if the 5V reference returns, indicating an internally shorted sensor.

3. 3

   Inspect the engine wiring harness for chafing, melting, or pinching against the engine block or frame.

4. 4

   Perform an ECM pin check by disconnecting the harness at the EDC7 module and verifying if the ECM outputs 5V directly at the pin.

1. 1

   Power Down

   Turn off the ignition and disconnect the battery ground cable to prevent electrical spikes.

2. 2

   Isolate the Short

   Using the machine's specific wiring diagram, locate the sensors tied to Sensor Supply 2 (commonly the DEF/UREA pressure sensor or atmospheric pressure sensor).

3. 3

   Test the Harness

   Disconnect the suspected sensor. Reconnect the battery, turn the key to the ON position (engine off), and probe the supply pin on the sensor connector with a multimeter.

4. 4

   Replace or Repair

   If the multimeter reads ~5.0V with the sensor unplugged: The wiring is good. Replace the internally shorted sensor. If the multimeter reads 0V or significantly less than 5V: The short is in the wiring harness. Trace the wire back to the EDC7 module, locate the short to ground, and repair the wire using heat-shrink butt connectors.

5. 5

   Clear Codes

   Reconnect all components, turn the key ON, and use the CNH Electronic Service Tool (EST) to clear the inactive fault codes. Run the engine to verify the code does not return.