New Holland ENG 123 – ENGINE: Boost Pressure Sensor voltage is too low.

The engine control module is receiving a voltage signal from the boost pressure sensor (MAP sensor) that falls below the minimum acceptable threshold, typically caused by a short to ground, an open circuit, or an internal failure. This causes the engine to derate to a 'no-boost fueling' condition, resulting in a noticeable loss of power.

• T6000
• T7
• T8 series
• TM 175
• CR9090
• CX8080
• CX8090
• MX Magnum series (215, 245, 275, 305, 335, 340)
• 7010 series

1. 1

   Inspect the wiring harness connecting the Boost Pressure Sensor to the Engine ECU for chafed wires, open circuits, or a short to ground.

2. 2

   Verify continuity between the sensor connector and pin A45 on the engine controller harness.

3. 3

   Disconnect the sensor and use a multimeter to verify that the ECU is sending the correct 5V reference voltage and ground to the sensor connector.

4. 4

   Check the sensor plug for dirt, moisture, or corroded pins.

1. 1

   Locate the Sensor

   Find the Boost Pressure Sensor, which is typically mounted on the intake manifold or just above the engine oil filter, depending on the specific engine block.

2. 2

   Disconnect and Remove

   Turn off the machine's battery power. Unplug the electrical connector from the sensor. Unbolt or unthread the faulty sensor from the manifold.

3. 3

   Install the New Sensor

   Insert the new OEM Boost Pressure Sensor, ensuring that the rubber O-ring/seal is properly seated to prevent boost leaks.

4. 4

   Reconnect Wiring

   Plug the electrical harness back into the sensor, ensuring the locking tab clicks into place.

5. 5

   Clear the Fault Code

   Connect a diagnostic scan tool to the machine's diagnostic port to clear the ENG 123 DTC from the Engine ECU's memory.

6. 6

   Test Operation

   Start the engine and verify that the code does not return and that the engine no longer derates under load.