Massey Ferguson 171.03 – Engine Control Unit (ECU): Ambient Temperature Sensor Voltage Issue

The sensor's input voltage is above normal or shorted high, indicating an open circuit (broken wire or disconnected plug) or a short circuit to a 5-volt power source.

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724

1. 1

   Locate the ambient air temperature sensor (often near the cab mirrors, front grill, or air intake).

2. 2

   Visually inspect the sensor's connector for disconnected pins, corrosion, or moisture ingress.

3. 3

   Trace the wiring harness from the sensor back to the ECU. Look for chafed wires, breaks (causing an open circuit), or wires melted together (causing a short to the 5V supply).

4. 4

   Disconnect the sensor and measure its internal resistance with a multimeter. If it reads as an open circuit (infinite resistance), the sensor has failed internally.

5. 5

   Verify with a dealer tool if the ECU requires a software calibration update, as some false voltage spikes can be resolved via software.

1. 1

   Disconnect the battery

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Repair wiring harness

   If wiring damage was found during diagnostics, splice and repair the damaged section of the harness using weather-sealed connectors.

3. 3

   Unplug the faulty sensor

   If the sensor is faulty, depress the locking tab on the 2-pin oval connector and unplug the harness.

4. 4

   Remove the old sensor

   Remove the old ambient temperature sensor (most are a simple push-in/pressed mounting clip or threaded brass body).

5. 5

   Install the new sensor

   Install the new sensor into the mounting bracket.

6. 6

   Reconnect the wiring harness

   Reconnect the wiring harness, ensuring the weather seal clicks firmly into place.

7. 7

   Clear the fault code

   Reconnect the battery, turn the ignition on, and use a diagnostic scan tool to clear the 000171.03 fault code.

8. 8

   Verify the repair

   Start the engine and verify the dashboard displays the correct ambient temperature and the code does not return.