Massey Ferguson 412.04 – Engine Control Unit (ECU): EGR Gas Temperature Sensor Low Voltage

The input voltage from the Exhaust Gas Recirculation (EGR) temperature sensor falls below the minimum required threshold. The engine controller interprets this abnormally low voltage as a potential short to ground in the circuit or a complete internal failure of the sensor, which may lead to improper engine performance, derating, and increased emissions.

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

1. 1

   Inspect the EGR temperature sensor and its associated wiring harness for signs of physical damage, melting, chafing, or corrosion.

2. 2

   Because the code specifies "Low Voltage," specifically look for wires that may be rubbed bare and shorting directly to the chassis/ground.

3. 3

   Use a digital multimeter or diagnostic scan tool to measure the sensor's voltage output. Confirm whether the voltage is actually dropping below the specified range.

4. 4

   Disconnect the sensor and check the pins on both the sensor side and the ECU harness side for pushed-out pins, moisture, or corrosion.

1. 1

   Power Down

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

2. 2

   Locate the Sensor

   Locate the EGR Gas Temperature Sensor, which is threaded into the exhaust/EGR cooler piping.

3. 3

   Disconnect

   Unplug the electrical connector from the sensor.

4. 4

   Wiring Repair (If Applicable)

   If the diagnostic checks revealed a short to ground in the harness, repair the damaged section of the wiring and apply heat-shrink tubing.

5. 5

   Sensor Replacement

   If the wiring is intact and the sensor is internally shorted, use a wrench to carefully unthread the old EGR temperature sensor from the exhaust piping. (Apply penetrating oil beforehand if the sensor is seized due to exhaust heat).

6. 6

   Install New Sensor

   Thread the new sensor into place and tighten to OEM torque specifications. Reconnect the electrical harness.

7. 7

   Clear Codes

   Reconnect the battery. Connect a diagnostic tool to the tractor's diagnostic port and clear the ECU fault codes.

8. 8

   Test Run

   Start the engine and allow it to reach operating temperature. Monitor the live data for the EGR temperature to ensure the new sensor is reading accurately and the 000412.04 code does not return.