New Holland NH 3025 – Engine ECU: Atmospheric Pressure Signal - SOURCE LOW

The voltage signal from the atmospheric (barometric) pressure sensor has fallen below the minimum acceptable threshold. A 'Source Low' condition typically means the sensor has internally shorted to ground or failed completely.

• T5 Series
• T6 Series
• T7 Series
• T8 Series
• Boomer Series
• 3040
• 3045
• 3050
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• Wheel Loaders
• W190B

1. 1

   Check for shared 5V reference faults: Look for other active codes for sensor supply voltages, as a shorted external sensor can pull down the 5V reference circuit inside the ECU

2. 2

   Verify ECU wiring: Inspect the main wiring harness connectors at the Engine ECU for moisture, corrosion, or pushed-out pins, and ensure the ECU has clean, solid grounds

3. 3

   Verify live data: Connect the New Holland Electronic Service Tool (EST) and monitor the 'Atmospheric Pressure' parameter. It should read approximately 100 kPa (14.5 psi) at sea level. A reading of 0 kPa confirms a dead sensor

1. 1

   Confirm fault

   Confirm the fault is active and the sensor reading is out of range via the EST diagnostic tool.

2. 2

   Disconnect battery

   Disconnect the battery negative terminal.

3. 3

   Remove ECU

   Disconnect the main harness connectors from the Engine ECU and unbolt the module from the engine block/mounting bracket.

4. 4

   Install new ECU

   Install the new Engine ECU.

5. 5

   Program ECU

   Connect the New Holland EST and perform the ECU programming procedure. You must flash the correct engine dataset, restore self-learning parameters, and input the specific injector trim codes for the engine.

6. 6

   Alternative repair

   If a new ECU is cost-prohibitive, the existing Engine ECU can be removed and sent to a specialized agricultural electronics repair facility to desolder the failed internal barometric pressure sensor and solder on a replacement.