John Deere 636.02 – Engine Control Unit (ECU): Camshaft Position Signal Invalid
Issue description
The controller is detecting an erratic, intermittent, or incorrect signal from the camshaft position sensor. The system specifically flags this when it detects excessive noise (extra pulses) or a signal mismatch on the camshaft position signal input.
Applies to these machines
55 machines- 5085E
- 5090E
- 5090EL
- 5100E
- 5065M
- 5075M
- 5085M
- 5100M
- 5100MH
- 5100ML
- 5115ML
- 5095M
- 5095MH
- 5105M
- 5015ML
- 5090M
- 5115M
- 6110M
- 6120M
- 6130M
- 6145M
- 6155M
- 6175M
- 6195M
- 6110R
- 6120R
- 6130R
- 6145R
- 6155R
- 6175R
- 6195R
- 6215R
- 8R series
- 135D
- 135G
- 190GW
- 230GW
- 245GLC
- 450DLC
- 444J
- 544J
- 624J
- 655B
- 755B
- 850J
- 670D
- 672D
- 770D
- 772D
- 870D
- 872D
- 319D
- 329D
- 345GLC
- Gator XUV series
Check the cause
Inspect the sensor cable connections and the wiring harness leading back to the ECU. Look for chafed wires, loose pins, or corrosion that could cause high resistance or signal noise.
Check if there are active codes for the Crankshaft Position Sensor (e.g., 637.02). If both the camshaft and crankshaft sensors fail or are out of sync, the engine will stall and will not restart. If only the camshaft sensor fails, the engine may hesitate or require prolonged cranking, but will usually still run.
Ensure there is no electromagnetic interference routing too close to the sensor wiring.
Repair steps
Disconnect power
Turn off the machine and disconnect the battery to prevent electrical shorts.
Locate the sensor
Locate the camshaft position sensor on the engine block (usually near the timing gear cover or cylinder head, depending on the specific engine model).
Repair harness
If the diagnostic checks revealed damaged wiring, repair the harness or replace the connector pigtail.
Remove the sensor
Disconnect the electrical connector from the sensor. Remove the mounting bolt(s) and pull the sensor out of its port.
Install the new sensor
Lubricate the O-ring on the new sensor with clean engine oil. Insert it into the port and torque the mounting bolt to OEM specifications.
Reconnect and clear codes
Reconnect the electrical harness and the battery. Turn the key to the ON position and use a diagnostic scan tool (like Service ADVISOR) to clear the stored 000636.02 fault code.
Test run
Start the engine. Verify that the prolonged cranking symptom is gone and that the code does not return.
Parts you might need
(6)Camshaft Position Sensor
RE519144Common magnetic pickup speed/position sensor used on a wide variety of John Deere agricultural and construction engines.
Camshaft Position Sensor
RE71121Engine camshaft position sensors used on various combine harvesters and dozers.
Camshaft Position Sensor
RE43511Engine camshaft position sensors used on various combine harvesters and dozers.
Camshaft Position Sensor
8973121081Camshaft position sensor for specific heavy equipment applications.
Camshaft Position Sensor
8980190240Used specifically on John Deere excavators (like the 135G, 245GLC, 345GLC) that are equipped with Isuzu 4HK1/6HK1 engines.
Camshaft Position Sensor
MIU12582Camshaft position sensor specific to smaller utility vehicles like the Gator XUV series.
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