Case IH 731 – Engine Control Module (ECM): Engine Speed / Position #2 -- Mechanical misalignment

The Engine Control Module (ECM) has detected that the engine position signal from the crankshaft position sensor does not match the signal from the camshaft position sensor. The ECM monitors the position of the missing tooth on the crankshaft speed sensor target and the camshaft speed sensor target; if they are out of phase, the ECM determines there is a mechanical misalignment or that the mechanical system is not responding properly. This condition will typically cause an amber Check Engine light, engine power derate, rough running, or a no-start condition.

• MX Magnum
• STX Steiger
• Magnum (MX/TG series)
• Steiger (STX, Rowtrac)
• Farmall (80N, 85C, 95C, 105C, 115C, etc.)
• Puma
• Maxxum
• Optum
• Luxxum
• Quantum series
• Case Loaders (570NXT, SR220, SV300)
• Dozers (750M)

1. 1

   Check for related active codes, specifically Fault Code 689 (Crankshaft Speed/Position Sensor) or Fault Code 778 (Camshaft Speed/Position Sensor)

2. 2

   Inspect sensor wiring and grounds for loose, missing, or corroded connections and harness damage leading to the camshaft and crankshaft sensors

3. 3

   Review recent repairs (if this code became active immediately following an engine rebuild or camshaft removal, the camshaft gear is likely installed incorrectly)

4. 4

   Inspect the tone wheel for loose capscrews at the crankshaft, damage to the sensor target teeth, or a loose tone wheel

1. 1

   Connect Diagnostic Tool

   Connect your electronic service tool (e.g., INSITE or Case IH equivalent) and verify the status of Fault Code 731.

2. 2

   Resolve Sensor Faults

   If codes 689 or 778 are present, test the 5-volt supply and return circuits to the sensors. Replace the camshaft or crankshaft position sensor if they are electrically dead or physically damaged.

3. 3

   Inspect the Crankshaft Tone Wheel

   If the sensors are functioning properly, remove the lubricating oil pan to visually inspect the crankshaft tone wheel.

4. 4

   Torque or Replace Capscrews

   Verify the torque of the crankshaft tone wheel capscrews. If the capscrews have backed out but the tone wheel is undamaged, replace and properly torque the capscrews. If the capscrews sheared off or the tone wheel detached, inspect the cylinder block and crankshaft for damage and replace the tone wheel.

5. 5

   Correct Engine Timing

   If the tone wheel is intact and the sensors are good, the mechanical timing is off. You must access the front gear cover/camshaft gear, re-align the timing marks, and ensure the camshaft is correctly pinned and timed to the crankshaft.

6. 6

   Clear Codes and Validate

   Once repairs are made, use the service tool to clear the inactive fault codes. Perform a key cycle, start the engine, and let it idle for 1 minute. The fault code status should change to INACTIVE and the amber CHECK ENGINE lamp will turn off.