New Holland ENG 222 – Engine Control Module (ECM): Ambient Air Pressure Sensor Voltage is too low.

The Engine Control Module (ECM) is receiving a voltage signal from the ambient air (barometric) pressure sensor that falls below the acceptable minimum threshold. This condition is typically caused by a short to ground in the sensor's signal circuit, a completely failed sensor, or a disconnected/damaged wiring harness.

• T6 series
• T7 series
• T8 series
• TG series
• TG210
• TG285
• TM series
• TM120
• TM190
• Magnum series
• CR series combines
• CX series combines
• FR series forage harvesters
• FR450

1. 1

   Inspect the wiring harness and the connector at the Ambient Air Pressure Sensor for physical damage, corrosion, moisture, or backed-out pins.

2. 2

   Disconnect the sensor and turn the key to the ON position. Verify that the sensor is receiving the correct reference voltage (typically 5V) and has a solid ground from the ECM.

3. 3

   Test the signal wire between the sensor connector and the ECM harness for continuity. Check that the signal wire is not shorted to ground, which is the primary trigger for a 'voltage too low' code.

4. 4

   If the wiring is intact, back-probe the signal wire with the sensor plugged in to see if the sensor is outputting a valid voltage based on current atmospheric pressure. If the voltage remains bottomed out, the sensor has failed internally.

1. 1

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the Ambient Air Pressure Sensor.

   Depending on the specific engine, this may be a standalone sensor mounted near the ECM, or integrated into a combination Manifold Absolute Pressure/Temperature (TMAP) sensor on the intake manifold.

3. 3

   Repair any chafed wiring or replace damaged connector pigtails identified during the diagnostic phase.

4. 4

   If the wiring tested good, remove the mounting hardware for the faulty Ambient Air Pressure Sensor and pull the sensor free.

5. 5

   Install the replacement sensor and torque the mounting hardware to OEM specifications. Reconnect the electrical harness.

6. 6

   Reconnect the battery.

7. 7

   Connect a diagnostic tool (such as the CNH Electronic Service Tool) to clear the inactive ENG 222 fault code.

8. 8

   Start the engine and verify that the code does not return and that the engine operates smoothly without derating.