John Deere 000637.07 – ECU: Crankshaft Position Sensor Signal Issue

The Engine Control Unit (ECU) has detected a problem with the signal coming from the crankshaft position sensor. This indicates a missing signal, an incorrect pattern, or a mismatch between the crankshaft and camshaft position sensors. As a result, the timing between the ECU and the fuel injection pump may be moderately out of sync, which can negatively affect proper engine operation and overall vehicle performance.

• 1570
• 1575
• 1580
• 1585
• 1600
• 2032R
• 2038R
• 3032E
• 3038E
• 3039R
• 3046R
• 4044M
• 4044R
• 4052M
• 4052R
• 4066M
• 4066R
• 328E
• 329E
• 330G
• 331G
• 332E
• 332G
• 333E
• 333G
• 5200
• 5210
• 6420
• 6330
• 7130
• 7930
• 8430
• STS combines

1. 1

   Scan for codes using a diagnostic tool to confirm 000637.07 and check for any other related codes.

2. 2

   Visually inspect the crankshaft position sensor, connector, and wiring harness for damage, corrosion, loose connections, or frayed wires.

3. 3

   Check the sensor tip for debris, as magnetic sensors can attract metal shavings that disrupt the signal.

4. 4

   Inspect the wiring from the ECU to the sensor; a new wire may be required if a fault is found in the harness.

5. 5

   Test the sensor with a multimeter: For inductive sensors, check resistance (typically 200-1,000 ohms; zero indicates a short, infinite indicates an open circuit) and AC voltage while cranking (0.5-1.5V).

6. 6

   For Hall effect sensors, verify a 5V reference, good ground, and pulsing DC voltage while cranking.

1. 1

   Locate the sensor

   Refer to the machine's service manual to find the crankshaft position sensor, typically located on the flywheel housing, engine block side, or front timing cover.

2. 2

   Disconnect the sensor

   Carefully unplug the electrical connector and inspect the plug for any damage or corrosion.

3. 3

   Remove the old sensor

   Remove the mounting bolt using the appropriate socket. Gently twist and pull the sensor straight out, as it may be snug due to the O-ring.

4. 4

   Prepare for installation

   Compare the new sensor to the old one. Clean the mounting surface and apply a small amount of clean engine oil to the new sensor's O-ring to aid sealing.

5. 5

   Install the new sensor

   Insert the new sensor into the mounting hole, hand-tighten the bolt, and then torque it to the manufacturer's specifications.

6. 6

   Reconnect and finalize

   Plug in the electrical connector until it clicks. Reinstall any removed covers, clear the fault codes with a scanner, and start the engine to verify the repair.