Case IH 753 – Engine Control Module (ECM): Synchronization has been lost

The engine position signal from the crankshaft position sensor (engine speed sensor) and the camshaft position sensor do not match up. The controller hardware detects a mechanical misalignment or a loss of the synchronized timing signals required for proper fuel injection.

• MX Magnum
• STX Steiger
• Magnum series tractors
• Steiger 4WD tractors
• Puma series tractors
• Farmall series tractors (e.g., 85C, 95C, 105C, 115C)
• Axial-Flow combines

1. 1

   Inspect the engine wiring harness circuits for both the camshaft position sensor and the crankshaft position sensor. Look for chafed wires, loose connector pins, or corrosion that could interrupt the signal to the ECM.

2. 2

   Check for accompanying active fault codes related to sensor voltage, such as open circuits or short-to-ground faults on the 5V supply line.

3. 3

   Connect the Case IH Electronic Service Tool (EST) or Cummins INSITE. Clear the inactive fault codes, cycle the keyswitch, start the engine, and let it idle for 1 minute to see if the code returns to ACTIVE.

4. 4

   Remove the sensors and inspect the tips. If there is metal debris on the magnetic tip or physical damage, it indicates internal mechanical misalignment or tone ring/gear damage.

1. 1

   Power Down

   Turn the keyswitch to the OFF position and disconnect the battery to prevent damage to the ECM.

2. 2

   Locate the Sensor

   Locate the faulty camshaft or crankshaft position sensor on the engine block or timing cover (location varies depending on the specific engine model).

3. 3

   Disconnect

   Unplug the electrical harness connector from the sensor.

4. 4

   Remove

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

5. 5

   Install

   Lubricate the O-ring on the new sensor with clean engine oil. Insert the new sensor into the bore and tighten the retaining bolt to the OEM torque specification.

6. 6

   Reconnect

   Plug the electrical harness connector back into the sensor.

7. 7

   Validate Repair

   Reconnect the battery. Turn the keyswitch ON, clear the inactive fault codes using your diagnostic tool, and start the engine. Let it idle for at least 1 minute to ensure the ECM turns off the Check Engine light and the code does not return.