Massey Ferguson E 9072 (31) – Engine Control Unit (ECU) / Sisu EEM3 / Bosch EDC7: Crankshaft speed sensor, reverse connected

The control module is receiving an inverted or reversed signal from the crankshaft speed sensor. This underlying condition is almost always an electrical polarity issue—typically caused by the sensor's two wires (signal and ground/reference) being pinned backward in the connector, a botched wiring harness repair, or an internal short/failure in the sensor causing the waveform to read in reverse.

• 5400 series
• 6400 series
• 7400 series
• 8400 series
• 8600 series
• MF 5455
• MF 5460
• MF 6460
• MF 6465
• MF 6480
• MF 7480
• MF 8480
• MF 8690

1. 1

   Check for recent repairs to determine if the engine wiring harness was recently repaired, repinned, or replaced.

2. 2

   Inspect the wiring harness connector at the crankshaft speed sensor to ensure the pins have not been swapped or installed backwards.

3. 3

   Verify if an aftermarket sensor was recently installed, as it may have been manufactured with internal reverse polarity.

4. 4

   Test the sensor wiring back to the EEM3 ECU for continuity, shorts, and correct pinout orientation.

1. 1

   Turn off the tractor.

   As recommended by Sisu EEM3 service guidelines, disconnect the battery or the main connector of the EEM3 control unit before performing electrical work.

2. 2

   Locate the crankshaft speed sensor.

   Locate the crankshaft speed sensor on the engine block.

3. 3

   Disconnect the electrical connector.

   Disconnect the electrical connector from the sensor.

4. 4

   Correct wiring orientation.

   If the wiring harness was recently repaired and the pins were swapped, use a pin extraction tool to remove the wires from the connector housing and re-insert them in the correct factory orientation.

5. 5

   Remove the faulty sensor.

   If the wiring is correct but the sensor itself is faulty or an incorrect aftermarket part, remove the sensor mounting bolt and pull the sensor from the engine block.

6. 6

   Install a new sensor.

   Install a new genuine AGCO/Sisu crankshaft speed sensor and tighten the mounting bolt.

7. 7

   Reconnect the electrical connector.

   Reconnect the electrical connector to the sensor.

8. 8

   Reconnect the ECU and battery.

   Reconnect the EEM3 ECU main connector and the battery.

9. 9

   Clear fault code and verify.

   Connect a diagnostic tool (such as the WinEEM3s Service Tool) to the tractor to clear the E 9072 (31) fault code and verify that the engine speed signal is reading correctly while cranking/running.