Case IH 19220 – Engine ECU: Over temperature on Blow By 3-way valve power stage output

The Engine Control Unit (ECU) has detected an overheating condition within its internal driver circuit (the "power stage") that operates the Blow By 3-way valve. This is almost always caused by excessive electrical current draw resulting from a short circuit to ground in the wiring harness, a short circuit to the battery, or an internal short within the valve's solenoid coil itself.

• Tier 4b
• FPT Tier 4 Final, Stage IV, and Stage V diesel engines
• Puma
• Optum
• Magnum
• Steiger
• Farmall Pro series (95U/105U/115U)
• N-Series Loader Backhoes

1. 1

   Wiring Harness Inspection: Trace the wiring harness from the Engine ECU to the Blow By 3-way valve. Look for chafed wires, melted insulation, or pinched areas that could cause a short circuit to ground or a short to battery voltage.

2. 2

   Valve Resistance Test: Disconnect the electrical connector at the Blow By 3-way valve. Using a multimeter, measure the resistance across the pins of the valve's solenoid coil. If the resistance is near zero (continuity), the coil is internally shorted and the valve must be replaced.

3. 3

   ECU Pin Inspection: Check the Engine ECU connector pins for corrosion, moisture, or damage that could be bridging circuits.

4. 4

   Voltage Check: Verify that the machine's battery and alternator output voltage are within normal specifications, as an over-voltage condition can also cause the power stage to overheat.

1. 1

   Power down machine

   Power down the machine, remove the key, and disconnect the negative battery cable to protect the ECU.

2. 2

   Locate valve

   Locate the Blow By 3-way valve on the engine. It is typically mounted near the valve cover or integrated into the crankcase breather/ventilation assembly.

3. 3

   Disconnect connector

   Disconnect the electrical connector from the valve.

4. 4

   Repair wiring

   If the diagnostic checks revealed damaged wiring, repair the harness using OEM-approved heat-shrink connectors and re-loom the wiring.

5. 5

   Disconnect hoses

   If the valve itself failed the resistance test, loosen the hose clamps and disconnect the crankcase ventilation hoses routed to the 3-way valve.

6. 6

   Remove mounting bolts

   Remove the mounting bolts securing the valve to the engine block or bracket.

7. 7

   Install new valve

   Install the new Blow By 3-way valve and tighten the mounting hardware.

8. 8

   Reconnect hoses

   Reconnect the ventilation hoses and secure them with the hose clamps.

9. 9

   Reconnect connector

   Reconnect the electrical connector to the new valve.

10. 10

    Reconnect battery

    Reconnect the negative battery cable.

11. 11

    Clear codes and verify

    Connect a diagnostic tool (such as the Case IH EST) to clear the inactive fault codes. Start the engine and verify that code 19220 does not return.