New Holland ENG 221 – Engine Controller (ENG): Ambient Air Pressure Sensor Voltage is too high.

The signal voltage returning from the ambient air pressure sensor (also known as a barometric pressure sensor) to the controller has exceeded the maximum expected threshold, which typically points to a 'shorted high' condition in the sensor circuit or a failed sensor.

• TG210
• TG230
• TG255
• TG285
• T7520
• T5040-T5070
• T9/T9000 Series
• CR9090
• CX8080 Elevation
• CX8090 Elevation
• FR450

1. 1

   Verify ECU Power and Ground: Verify that the supply power and earth (ground) to the engine ECU are functioning properly.

2. 2

   Determine Sensor Location/Type: Determine if your specific machine has a standalone sensor on the engine harness or an integrated sensor within the PMCI-2 ECU.

3. 3

   Circuit Inspection: If the sensor is external, inspect the wiring harness between the sensor and the ECM for a 'shorted high' condition. Look for rubbed wires, corrosion in the connector, or bent pins.

4. 4

   Diagnostic Tool Verification: Use a PC-based service tool or the New Holland Diagnostic Tool to read the live voltage of the ambient air pressure sensor to confirm it is pegged high.

1. 1

   Disconnect battery

   Turn off the key and disconnect the battery ground circuit to prevent electrical spikes.

2. 2

   Remove external sensor

   For External Sensors (e.g., 8.3L/9L engines): Locate the ambient air pressure sensor on the engine block/harness. Disconnect the sensor wiring harness connector. Remove the mounting hardware and pull the faulty sensor.

3. 3

   Install external sensor

   Install the new ambient air pressure sensor and secure the mounting hardware. Reconnect the wiring harness, ensuring the connector clicks into place and is free of debris.

4. 4

   Replace Engine Control Module

   For Integrated Sensors (e.g., PMCI-2 ECU): If diagnostic tests confirm the internal sensor has failed and power/ground to the ECU are good, the Engine Control Module itself must be replaced or sent out for specialized repair.

5. 5

   Reconnect battery

   Reconnect the battery ground circuit.

6. 6

   Clear fault code

   Connect your diagnostic service tool, clear the ENG 221 fault code, and run the engine to verify the code does not return.