Case IH 951 – Engine Control Module (ECM): A power imbalance between the cylinders was detected by the controller hardware.

The Engine Control Module (ECM) calculates the power output of each cylinder at engine idle speeds by monitoring the instantaneous acceleration of the crankshaft as each injector fires. If the ECM detects that a specific cylinder has an abnormally high or low contribution to the engine speed (exceeding pre-defined limits), it logs this fault. This code is primarily intended to assist in troubleshooting performance complaints such as engine misfires, rough idling, and low power.

• MX Magnum
• STX Steiger
• Magnum series
• Steiger series
• Puma series
• Farmall series
• Axial-Flow series (7120, 8120, 9120, 2388)

1. 1

   Connect the Case IH Electronic Service Tool (EST) or Cummins INSITE and run a cylinder cut-out test at idle to identify exactly which cylinder is underperforming.

2. 2

   Check for air being ingested into the fuel system by inspecting all fuel supply lines, filters, and fittings for suction leaks.

3. 3

   Remove the valve cover and check the valve lash (overhead adjustment), comparing the actual valve lash to the manufacturer's reset limits.

4. 4

   Listen for an intake valve 'chirping' noise in the intake, which indicates a damaged or stuck-open valve.

5. 5

   Check for excessive crankcase blowby when the engine is loaded, which indicates piston, ring, or cylinder damage.

6. 6

   Inspect the intake and exhaust passages for signs of oil or coolant, which points to a damaged cylinder head or head gasket.

1. 1

   Verify the Fault

   Turn the keyswitch ON and connect the diagnostic tool to confirm ENG 951 is active.

2. 2

   Bleed/Seal the Fuel System

   If air intrusion is found during diagnostics, tighten loose fuel fittings, replace damaged fuel lines or filter O-rings, and bleed the fuel system.

3. 3

   Adjust the Overhead

   If the valve lash was found to be out of specification, perform a complete overhead adjustment (valves and injectors) to OEM specifications.

4. 4

   Replace the Faulty Injector

   If no air is in the fuel system and the valve lash is correct, the most common culprit is a faulty fuel injector on the cylinder identified during the cut-out test. Remove and replace the bad injector.

5. 5

   Address Mechanical Failures

   If the injector does not solve the issue, perform a compression or leak-down test. You may need to remove the cylinder head to repair a blown head gasket, damaged valves, or extreme camshaft wear.

6. 6

   Validate the Repair

   Clear the fault codes using the diagnostic tool. Perform a key cycle, start the engine, and let it idle for at least 1 minute. The ECM will run the diagnostic continuously; if the repair was successful, the code will change to INACTIVE and the Check Engine lamp will turn off.