Case IH F-636-02 - ECU – Engine Control Unit (ECU): Camshaft speed sensor pattern is not plausible

The Engine Control Unit (ECU) has detected an improper pattern, excessive electrical noise, or an invalid signal rate of change on the camshaft position sensor input. It can also indicate that the compared values between the camshaft speed sensor and the crankshaft speed sensor are mismatched or out of limits. The engine may require a longer cranking time to start.

• MAGNUM AFS Connect
• Farmall series (40, 45, 50, 60, 80N, 80V, 85C, 95C, 100N, 105C, 115C)
• Maxxum series (110-140 EP)
• Puma series (200, 230)
• Magnum series
• Steiger series
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• 7230
• 8230
• 9230
• Farmlift series
• compact track loaders

1. 1

   Verify the fault code is currently active using the electronic service display.

2. 2

   Inspect the relevant wiring harnesses and the 3-pin connector at the camshaft speed sensor for damaged wires, bent or dislocated pins, and corroded terminals.

3. 3

   Perform a harness flex test: Verify connectors are fully seated, then flex the involved wiring harnesses while monitoring the service display to reveal any intermittent breaks or short circuits.

4. 4

   Check the physical condition and correct positioning of the camshaft signal wheel and the crankshaft signal wheel, as a physical offset can trigger the plausibility error.

5. 5

   If wiring and sensor are intact, check the Engine ECU (A-095) for the appropriate software version and re-flash the ECU if necessary.

1. 1

   Disconnect power

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical shorts.

2. 2

   Locate sensor

   Locate the camshaft speed sensor on the engine block (location varies slightly depending on the specific FPT/Iveco engine model).

3. 3

   Disconnect harness

   Disconnect the 3-pin electrical connector from the sensor.

4. 4

   Remove fastener

   Remove the retaining fastener securing the sensor to the block. This is typically an M6 x 1 x 20mm flange bolt.

5. 5

   Remove old sensor

   Pull the old camshaft speed sensor straight out of its bore.

6. 6

   Prepare new sensor

   Lubricate the O-ring on the new sensor with a small amount of clean engine oil.

7. 7

   Install new sensor

   Insert the new camshaft speed sensor into the bore and install the retaining bolt. Torque to OEM specifications (usually standard M6 torque).

8. 8

   Reconnect harness

   Reconnect the 3-pin electrical harness connector, ensuring the locking tab clicks into place.

9. 9

   Reconnect power

   Reconnect the battery.

10. 10

    Verify repair

    Start the engine and use the diagnostic display to verify that the F-636-02 / 3091 fault code has moved from 'Active' to 'Inactive' or cleared entirely.