New Holland DCU 19677 – DCU (Dosing Control Unit): Ambient Temperature: SAE J1939 Check for CAN receive signal : (Signal Range Check: Signal not in range / Erroneous Signal / Signal not available) _timeout _P0071 Ambient Air Temperature Sensor Range/Performance

The control module has lost communication with the Ambient Air Temperature Sensor over the SAE J1939 CAN bus network, or the signal being received is completely out of the expected scale (erroneous/unavailable), resulting in a timeout. This triggers the standard OBD2 equivalent code P0071 (Ambient Air Temperature Sensor Range/Performance).

• New Holland T5
• New Holland T6
• New Holland T7
• New Holland T8
• New Holland T9
• New Holland T7.220
• New Holland T7.235
• New Holland T7.250
• New Holland T7.260
• New Holland T7.270
• New Holland T8.xxx Series
• New Holland T6000
• New Holland T7000
• New Holland CX
• New Holland CR

1. 1

   Check for related companion codes (such as DCU 19678 or DCU 19679). If multiple sensors are failing simultaneously, the issue is likely a shared CAN bus wiring fault or a shared ground.

2. 2

   Visually inspect the wiring harness and the connector at the Ambient Air Temperature Sensor (located near the clean-air induction tract, air filter housing, or front grille) for chafed wires, corrosion, or loose connections.

3. 3

   Verify the integrity of the SAE J1939 CAN lines between the sensor, the Engine ECU, and the DCU using a multimeter to check for continuity and proper voltage.

4. 4

   Measure the resistance of the ambient air temperature sensor to see if it aligns with the expected ohms for the current outside temperature. An open (infinite resistance) or shorted reading indicates internal sensor failure.

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery cable to prevent electrical shorts while working on the CAN bus system.

2. 2

   Locate the Sensor

   Locate the Ambient Air Temperature Sensor. Depending on the exact model, it is either mounted directly in the intake manifold/boost piping (as a combined MAP/Temp sensor) or near the air filter housing.

3. 3

   Remove the Faulty Sensor

   Depress the locking tab on the electrical pigtail and disconnect the harness. Unthread or unbolt the sensor from its mounting location.

4. 4

   Install the New Sensor

   Insert the replacement sensor and tighten it to the manufacturer's specifications.

5. 5

   Reconnect

   Plug the electrical connector back in, ensuring the weather seal is intact and the locking tab clicks into place. Reconnect the battery.

6. 6

   Clear Codes

   Connect a diagnostic tool (such as the CNH Electronic Service Tool) to clear the DCU 19677 / P0071 fault codes. Run the engine and verify that the ambient temperature reads correctly on the dash/monitor and that the code does not return.