Massey Ferguson 004201.31 – ECU: Crankshaft Speed Sensor Signal Issue

The Engine Control Unit (ECU) detects that there is no signal coming from the Crankshaft Speed Sensor. This sensor monitors the rotational speed and position of the engine's crankshaft, which is essential data for the ECU to properly control fuel injection timing and ignition. Without this signal, the engine's timing and performance are compromised, leading to symptoms such as the engine cranking but not starting, sudden stalling, rough running, misfiring, reduced power, and an illuminated check engine light.

• 5460
• 5465
• 5470
• 5475
• 5480
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 6460
• 6465
• 6470
• 6475
• 6480
• 6485
• 6490
• 6495
• 6497
• 6499
• 6612
• 6613
• 6614
• 6615
• 6616
• 6712
• 6713
• 6714
• 6715
• 6716
• 6718
• 7465
• 7475
• 7480
• 7485
• 7490
• 7495
• 7497
• 7499
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726
• 8450
• 8460
• 8470
• 8480
• 8650
• 8660
• 8670
• 8680
• 8690
• 8727
• 8730
• 8732
• 8735
• 8737
• 9500 Series Combine
• 9600 Series Combine
• 9700 Series Combine
• Telehandlers

1. 1

   Use a diagnostic scanner to confirm that 004201.31 is the active fault code and note any other related codes.

2. 2

   Visually inspect the crankshaft speed sensor (typically located on the engine block near the crankshaft pulley or flywheel) and its wiring harness for physical damage, corrosion, or contamination from dirt and oil.

3. 3

   Disconnect the sensor and inspect the electrical connector for bent, corroded, or loose pins to ensure a secure connection.

4. 4

   Perform a continuity test on the signal and ground wires between the sensor connector and the ECU connector to check for open circuits or shorts.

5. 5

   With the ignition off and the sensor disconnected, measure the resistance across the sensor's terminals using a multimeter. For some models, expected resistance is approximately 450 ohms +/- 20 ohms at room temperature. An open or shorted reading indicates a faulty sensor.

6. 6

   Use a diagnostic tool to monitor live engine RPM data while cranking. A reading of zero RPM while the engine is turning over strongly suggests a crankshaft sensor signal problem.

7. 7

   If the sensor is a 3-wire Hall-effect type, check for a power supply (typically 5V or 12V) and a good ground at the connector with the ignition on. Back-probe the signal wire while cranking the engine to verify the voltage switches or fluctuates.

1. 1

   Disconnect the Battery

   For safety, disconnect the negative battery terminal.

2. 2

   Locate the Sensor

   Identify the crankshaft speed sensor on the engine block. Its location can vary, so a service manual for the specific tractor model is recommended.

3. 3

   Remove the Sensor

   Disconnect the electrical connector from the sensor. Remove the one or two bolts that secure the sensor to the engine block.

4. 4

   Clean the Mounting Surface

   Thoroughly clean the sensor's mounting surface on the engine block to ensure proper installation and air gap.

5. 5

   Install the New Sensor

   Apply a light coat of anti-seize to the threads of the new sensor. Manually screw the sensor in until it makes contact, then follow the manufacturer's specific instructions for setting the air gap, which may involve unscrewing it a set amount (e.g., 3/4 of a turn) before tightening the locknut. Torque the mounting bolts and locknut to the specified value.

6. 6

   Reconnect and Test

   Reconnect the electrical connector to the new sensor. Reconnect the battery. Start the engine to ensure it runs smoothly. Use a diagnostic scanner to clear any stored fault codes.