Case IH 19519 – Engine Control Unit (ECU) / Vehicle Control Module (VCM): Injection quantity at low idle below minimum value

The engine control system is commanding a fuel injection quantity to maintain low idle that is below the minimum expected threshold. This usually indicates that a fuel injector is defective and stuck in the open position (or leaking), causing excess uncommanded fuel to enter the cylinder and forcing the engine computer to pull back the commanded fuel quantity to prevent idle speed surging.

• Tier 4b
• Case N-Series Tractor Loader Backhoes (TLBs)
• Case IH Puma
• Case IH Maxxum

1. 1

   Warm the engine up to normal operating temperature

2. 2

   Run the engine in standard low idle

3. 3

   Remove all parasitic engine loads: turn off the air conditioning (AC), turn off all lamps, and disable any additional auxiliary hydraulics or PTO

4. 4

   Using a diagnostic service tool, check the live injection quantity values

1. 1

   Establish baseline idle

   Perform the diagnostic checks to establish a baseline warm, no-load idle.

2. 2

   Perform injector cutoff test

   If the injection quantity is still reading too low (meaning the failure is actively detected), perform an injector cutoff test via the diagnostic tool to identify which specific injector is over-fueling/stuck open.

3. 3

   Replace defective injector(s)

   Replace the defective fuel injector(s).

4. 4

   Evaluate for transient issue

   If the injection quantity normalizes and the fault does not return under the warm, no-load condition, you can ignore the failure as it may have been a transient issue.

5. 5

   Clear codes and test

   Clear the fault codes and test run the machine.