Massey Ferguson E 9071 (31) – Engine Control Unit (ECU) / Electronic Engine Management (EEM3) / Tractor Processing Unit (TPU): Crankshaft speed sensor: Crankshaft speed signal, too many pulses

The Engine Control Unit (ECU) has detected an abnormal number of pulses from the crankshaft speed sensor within a specific period of engine rotation. Instead of a clean signal corresponding to the teeth of the crankshaft's reluctor wheel, the ECU is receiving additional, unexpected signals. This can be caused by electrical interference, a faulty sensor, or a mechanical issue with the sensing components, and may result in rough running, poor fuel economy, and difficulty starting.

• 8650
• 8660
• 8670
• 8680
• 8690
• 6465
• 6475
• 6480
• 6490
• 6495
• 6497
• 6499
• 7465
• 7475
• 7480
• 7485
• 7490
• 7495
• 7497
• 7499
• 8400 series
• 9500 series combines

1. 1

   Inspect the wiring harness between the crankshaft speed sensor and the ECU for chafed wires, melted insulation, or shorting to the chassis that could introduce electrical noise.

2. 2

   Check the sensor and ECU connectors for water ingress, corrosion, or loose/backed-out pins.

3. 3

   Remove the crankshaft speed sensor and inspect the magnetic tip for accumulated metal shavings or debris.

4. 4

   Inspect the tone ring/gear through the sensor mounting hole while manually barring the engine over, checking for damaged, bent, or missing teeth and foreign debris.

1. 1

   Disconnect Power

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

2. 2

   Clean the Area

   Locate the crankshaft speed sensor on the engine block. Clean the surrounding area to prevent dirt from falling into the engine when the sensor is removed.

3. 3

   Remove the Sensor

   Unplug the electrical connector. Remove the retaining bolt and carefully pull the sensor out of the block.

4. 4

   Inspect and Clean

   If the sensor is simply covered in metallic sludge, clean it thoroughly, reinstall it, and test the machine to see if the code clears.

5. 5

   Replace the Sensor

   If the wiring is intact, the tone wheel is undamaged, and cleaning does not resolve the issue (or if the sensor is physically damaged), install a new OEM crankshaft speed sensor. Ensure the O-ring is properly seated and lubricated with a small amount of clean engine oil.

6. 6

   Reassemble and Clear Codes

   Torque the retaining bolt to OEM spec, reconnect the wiring harness, and reconnect the battery. Use a diagnostic tool to clear the E 9071 (31) / SPN 9071 fault code.

7. 7

   Test Run

   Start the engine and verify that it idles smoothly without misfires and that the fault code does not return.