New Holland ENG 1011 – Engine ECU (Engine Control Module): Battery 5 V Reference 1 Circuit High

The Engine Control Module (ECU) outputs a regulated 5-volt reference signal to power various 3-wire engine sensors (such as the manifold absolute pressure (MAP) sensor, oil pressure sensor, fuel pressure sensor, and accelerator pedal position sensor). A "Circuit High" condition means the ECU is detecting a voltage on this specific 5V reference circuit that is higher than the expected 5 volts. This is almost always caused by the 5V reference wire shorting to a 12-volt battery source, an internally shorted sensor feeding voltage back into the circuit, or an internal failure within the ECU itself.

• 200 Series Skid Steer Loaders (L220, SR130, SR160, SR175)
• Compact Track Loaders (TR270)
• Tractors and Combines utilizing the same CNH/Cummins engine architecture

1. 1

   Sensor Isolation Test: Disconnect the sensors on this circuit one at a time (e.g., oil pressure, boost pressure, fuel pressure). Check the active fault codes or measure the reference voltage at the connector after unplugging each one. If the voltage returns to a normal 5V (or the ENG 1011 code goes inactive and changes to a sensor-specific open circuit code), the sensor you just unplugged is internally shorted.

2. 2

   Harness Inspection: If unplugging the sensors does not drop the voltage back to 5V, inspect the engine wiring harness. Look for chafing, melted insulation, or pinched areas where the 5V reference wire might be rubbing against a 12V power supply wire.

3. 3

   ECU Pin Check: Inspect the Engine ECU connectors for moisture, corrosion, or bent pins.

4. 4

   ECU Isolation: Disconnect the engine harness from the ECU. Turn the key ON and probe the 5V Reference 1 pin directly on the ECU. If the ECU is outputting 12V (battery voltage) instead of 5V with nothing connected to it, the Engine ECU has failed internally.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the machine's negative battery cable to prevent electrical spikes.

2. 2

   Replace Faulty Component

   If a sensor failed: Remove the internally shorted sensor and install a new OEM replacement. If the harness is shorted: Open the wire loom at the site of the damage. Repair the shorted wires using solder and marine-grade heat shrink, or replace the entire engine wiring harness if the damage is extensive. If the ECU failed: Remove the faulty Engine ECU and install a replacement. (Note: A new ECU will require flashing/programming with the CNH Electronic Service Tool).

3. 3

   Reassemble

   Reconnect all sensor connectors and the ECU harness. Ensure the wire loom is secured away from high-heat sources and sharp brackets to prevent future chafing.

4. 4

   Clear Codes and Test

   Reconnect the battery. Turn the key ON and use a diagnostic scan tool to clear the ENG 1011 fault code. Start the engine and verify that the code does not return and that all sensor data reads normally.