Massey Ferguson 00.2.38 – Dash: Signal Voltage From Engine Speed Sensor Issue Dyna 4, Dyna 6

The control system is receiving an erratic, out-of-range, or missing electrical signal from the engine speed sensor. This sensor reads the crankshaft position/RPM and feeds critical data to the tractor's modules to manage fuel injection timing, transmission shifting, and engine protection systems.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5455
• 5460
• 5470
• 5608-5613
• 6460
• 6470
• 6480
• 6499
• 6612-6616
• 6712S-6718S
• 7465-7480
• 7614-7626
• 7714-7726S
• 8450-8480
• 8727-8737

1. 1

   Visual Inspection: Check the sensor and the two-pin connector for status and corrosion.

2. 2

   Resistance Test: With the engine stopped and the sensor disconnected, measure the resistance across the sensor pins at ambient temperature. It should read 450 Ohms +/- 20 Ohms.

3. 3

   Voltage Test: Check for alternating voltage (AC) output from the sensor while the engine/gear is turning (cranking).

4. 4

   Harness Integrity: Test the wiring harness between the sensor and the Dash module for continuity, proper insulation, and ensure there are no short-circuits to positive or ground. Note that on the two-pin connector, Pin 1 is the signal and Pin 2 is earth/ground.

1. 1

   Locate the Sensor

   The engine speed sensor is typically mounted on the flywheel housing or timing cover where it reads the crankshaft position.

2. 2

   Disconnect

   Unplug the two-pin electrical connector from the sensor.

3. 3

   Remove

   Remove the retaining bolt holding the sensor in place. (Note: Be prepared for seized bolts, as the sensor is exposed to heavy engine bay heat and debris). Carefully pull the old sensor out of the housing.

4. 4

   Clean

   Thoroughly clean the mounting area to ensure the new sensor seats perfectly flat. Debris here can throw off the sensor gap and cause immediate signal issues.

5. 5

   Install

   Insert the new sensor, ensuring the gap is correct for proper operation, and tighten the retaining bolt.

6. 6

   Reconnect

   Plug the wiring harness back in.

7. 7

   Clear Codes

   Connect to the tractor using Massey Ferguson Wintest or EDT diagnostics software to clear the fault code and verify the signal is reading correctly.