New Holland NH 3020 – Engine Controller (Engine ECU / EDC7): Boost Pressure Signal - SOURCE LOW

This fault code indicates that the voltage signal returning from the boost pressure sensor to the controller is below the minimum acceptable threshold. This usually points to a short circuit to ground, an open circuit (broken wire or disconnected sensor), or a completely failed sensor. The engine may enter a derated (limp) mode to protect itself.

• T6.120
• T6.140
• T6.150
• T6.160
• T6.175
• T7.170
• T7.200
• T7.210
• T9000 Series
• TM Series
• MXM Series
• Magnum
• Steiger
• Titan Floater

1. 1

   Check the wiring harness and connector at the boost pressure sensor (located on the intake manifold) for visible damage, corrosion, or backed-out pins.

2. 2

   Disconnect the sensor and turn the key to the ON position (engine off). Measure the reference voltage from the ECU to the sensor connector (should be approx 5 Volts).

3. 3

   Verify that the sensor ground circuit has good continuity to the ECU ground.

4. 4

   Check the signal wire for continuity between the sensor connector and the ECU pin. Ensure the signal wire is not shorted to ground (which directly causes the 'SOURCE LOW' condition).

5. 5

   Remove the sensor and inspect the tip. Heavy soot or carbon buildup can block the sensor port, though this typically causes erratic readings rather than a hard 'Source Low' electrical fault.

1. 1

   Power Down

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

2. 2

   Locate the Sensor

   Locate the boost pressure sensor (often a combined MAP/IAT sensor) on the engine's intake manifold.

3. 3

   Disconnect

   Carefully depress the locking tab on the electrical connector and pull it free from the sensor.

4. 4

   Remove

   Remove the mounting bolt(s) securing the sensor to the intake manifold. Gently pull the old sensor out of the manifold port, being careful not to let any dirt or debris fall into the intake.

5. 5

   Install

   Lightly lubricate the O-ring on the new sensor with clean engine oil. Press the new sensor firmly into the intake manifold port.

6. 6

   Secure

   Reinstall the mounting bolt(s) and tighten to OEM specifications.

7. 7

   Reconnect

   Plug the electrical wiring harness back into the sensor until the locking tab clicks.

8. 8

   Clear Codes

   Reconnect the battery. Turn the key on and use a diagnostic tool (such as the CNH Electronic Service Tool - EST) to clear the NH 3020 fault code.

9. 9

   Test

   Start the engine and verify that the code does not return and that the machine operates with full power under load.