John Deere 524225.31 – Engine Control Unit (ECU): Issue With Signal From Crankshaft Position Sensor

The control unit has detected an improper pattern, electrical noise, or an invalid signal coming from the crankshaft speed sensor while the ignition is ON. This indicates that the engine control unit is reading engine RPM (crankshaft movement) without receiving a valid start signal from the ignition switch, often due to the starter being bypassed/jumped or a wiring failure in the start signal circuit.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 5045E
• 5055E
• 5065E
• 5085E
• 5090E
• 5100E
• 5085M
• 5090M
• 5100M
• 5115M
• 210K
• 210LE
• 210LJ
• 260E
• 310E
• 770G
• 772G

1. 1

   Inspect Sensor Wiring and Connectors: Check the wiring harness leading to the Crankshaft Position Sensor for frayed wires, loose connections, or corrosion.

2. 2

   Check the Start Signal Circuit: Verify that the ignition switch and starter relay are functioning correctly. Ensure the ECU is receiving the 12V start signal when the key is turned to the crank position.

3. 3

   Check for Electrical Interference: Inspect the routing of the sensor wiring. Ensure it is not routed too close to high-voltage components or alternators that could introduce electromagnetic noise into the signal.

4. 4

   Verify Sensor Alignment and Mounting: Ensure the sensor is securely mounted to the timing gear cover or engine block and is properly aligned to read the reluctor wheel.

5. 5

   Test the Sensor: Use a digital multimeter or John Deere Service ADVISOR to monitor the crankshaft speed signal while cranking to verify if the sensor is outputting a consistent frequency/voltage.

1. 1

   Turn off the engine, remove the key, and disconnect the negative battery cable.

   Ensure the machine is powered down and safe to work on.

2. 2

   Locate the Crankshaft Position Sensor.

   Typically mounted on the timing gear cover or the side of the engine block near the crankshaft pulley.

3. 3

   Disconnect the wiring harness connector from the sensor.

   Carefully unplug the electrical connection.

4. 4

   Remove the retaining bolt and carefully pull the sensor out of its mounting bore.

   Extract the faulty sensor from the engine block or timing gear cover.

5. 5

   Clean the mounting surface and bore.

   Ensure no dirt falls into the engine during the replacement process.

6. 6

   Coat the O-ring of the new Crankshaft Position Sensor.

   Use TY6333 High-Temperature Grease (or equivalent clean engine oil) to prevent tearing during installation.

7. 7

   Install the new sensor into the timing gear cover/block.

   Tighten the retaining bolt to OEM torque specifications.

8. 8

   Reconnect the wiring harness connector.

   Ensure the connection is secure.

9. 9

   Reconnect the battery, turn the ignition ON, and clear the ECU fault codes.

   Use a diagnostic tool to clear codes, then start the engine and monitor to ensure the code does not return.