Massey Ferguson E171.04 – Engine ECU: Ambient Temperature Sensor Voltage Issue

The input voltage in the sensor circuit has dropped to a level that is outside its normal operating range, indicating low resistance to ground (a shorted/grounded circuit) or a completely failed sensor.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 4700 Series
• 4707
• 4708
• 4709
• 4710
• 5600 Series
• 5613 iT4
• 5700SL Series
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 8600 Series

1. 1

   Inspect the ambient temperature sensor and its wiring harness for physical damage, rubbing, or melted insulation that could cause a short to ground.

2. 2

   Disconnect the sensor and check the pins for corrosion, moisture, or pushed-out terminals.

3. 3

   Use a multimeter to check the signal wire between the sensor connector and the Engine ECU for a short to ground. If the wiring is intact and not grounded, the sensor itself has likely failed internally.

1. 1

   Power Down

   Turn off the ignition and disconnect the battery to prevent electrical spikes while working on ECU-monitored sensors.

2. 2

   Locate the Sensor

   Locate the ambient temperature sensor (typically mounted at the front of the tractor near the cooling package/grille or on the cab exterior, depending on the exact model series).

3. 3

   Remove the Sensor

   Depress the locking tab on the oval 2-pin electrical connector and pull it off the sensor. Unclip or unthread the sensor from its mounting bracket.

4. 4

   Install the New Sensor

   Press the new sensor into the mounting location until secure.

5. 5

   Reconnect

   Plug the electrical connector back in, ensuring it clicks into place. Reconnect the battery.

6. 6

   Clear Codes

   Use a compatible diagnostic service tool (such as the AGCO WinEEM3s/WinEEM4 Service Tool) to clear the inactive E171.04 / SPN 171 FMI 4 fault code from the Engine ECU memory.