Case IH 19588 – Engine Control Unit (ECU) / Engine Control Module (ECM): Too low oil viscosity

The Engine Control Unit (ECU) has determined that the engine oil has degraded, thinned out, or lost its lubricating properties. This is a calculated value based on engine run time, the number of active DPF regenerations, and calculated fuel-in-oil dilution.

• Tier 4b
• Farmall series (e.g., Farmall 115U)
• N-Series Tractor Loader Backhoes (e.g., 580N, 580 Super N, 590 Super N)

1. 1

   Check the engine oil dipstick for an abnormally high fluid level (above the MAX line), which strongly indicates fuel dilution in the oil pan.

2. 2

   Inspect the oil condition by smelling for a strong diesel fuel odor and observing if it drips off the stick excessively thin like water.

3. 3

   Review maintenance history to determine how many hours have passed since the last oil and filter change.

4. 4

   Scan the ECU for other fault codes related to frequent DPF regenerations, leaking fuel injectors, or high crankcase pressure, as these are root causes of fuel washing into the oil.

1. 1

   Drain the Oil

   Safely drain the degraded engine oil from the oil pan and remove the old engine oil filter.

2. 2

   Replace the Filter

   Lubricate the gasket of the new OEM engine oil filter and install it.

3. 3

   Refill the Engine

   Fill the engine with the correct capacity and grade of engine oil specified in your operator's manual (typically a heavy-duty diesel engine oil like 15W-40 or 10W-40, depending on climate).

4. 4

   Perform an ECU Reset

   Connect a diagnostic service tool (such as the CNH Electronic Service Tool - EST) to the machine's diagnostic port. Because the viscosity is a calculated value, simply changing the oil will not clear the fault code.

5. 5

   Reset Oil Change / DPF Dilution

   Navigate to the Engine Control Unit menu and perform the "Oil Change Reset" or "DPF/Oil Dilution Reset" routine. This tells the ECU algorithm that fresh oil has been introduced, resetting the calculated viscosity value to 100%.

6. 6

   Clear Codes

   Clear the inactive 19588 fault code from the ECU memory.

7. 7

   Test Run

   Start the engine, check for leaks at the filter, and verify that the fault code does not return.