Massey Ferguson 171.19 – Engine Control Unit (ECU): Ambient Temperature Sensor Issue (ECU)

Ambient temperature CAN signal is missing. The engine control module is not receiving the expected ambient air temperature data over the CAN bus network, which it relies on to adjust fuel delivery and injection timing for proper combustion.

• 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

   Test the CAN bus communication lines between the ambient air temperature sensor and the Engine ECU.

2. 2

   Inspect the wiring harness leading to the sensor (in the intake tract) for chafed wires, corrosion, or loose connector pins.

3. 3

   Look for accompanying codes such as SPN 171 FMI 3 or FMI 4 that indicate a hard electrical short or open wire.

4. 4

   Test the sensor's resistance with a multimeter to check for internal failure.

1. 1

   Disconnect battery

   Power down the tractor and disconnect the battery to protect the ECU and CAN network.

2. 2

   Locate sensor

   Locate the ambient air temperature sensor in the intake tract.

3. 3

   Clean contacts

   Disconnect the electrical harness from the sensor. Clean the contacts with electronic cleaner if dirt or corrosion is present.

4. 4

   Remove faulty sensor

   If the wiring tests fine but the CAN signal remains missing, the sensor's internal module has likely failed. Unbolt/unscrew the faulty sensor from the intake tract.

5. 5

   Install replacement sensor

   Install the replacement sensor.

6. 6

   Reconnect wiring and battery

   Reconnect the wiring harness and the battery.

7. 7

   Clear fault codes

   Clear the fault codes from the ECU using a diagnostic tool.

8. 8

   Verify repair

   Run the engine and verify that the code 000171.19 does not return and that engine power is fully restored.