Case IH 3191 – Engine Control Module (ECM): Cylinder2Warning - Application Dependent

Fault code 3191 indicates a "Cylinder 2 Warning - Application Dependent". This code is triggered when the engine control system detects an anomaly with the fuel injector or the combustion performance on Cylinder 2. The "Application Dependent" designation means that the engine's programmed response to this failure (such as triggering an engine derate, limiting RPMs, or forcing a shutdown) depends on the specific vehicle and how its software is configured for its application. It is frequently accompanied by related electrical fault codes such as 3192 (Open Load) or 3193 (Current Level Error).

• Case IH Magnum 235 – 340 (Series 4)
• Case IH Steiger series
• Case IH Vestrum series
• Case IH Maxxum series

1. 1

   Use the CNH EASy diagnostic tool to check for related electrical codes on Cylinder 2, such as 3192 (Open Load) or 3193 (Current Level Error), which point directly to a wiring or solenoid failure.

2. 2

   Inspect the wiring harness connecting the Engine ECM to the Cylinder 2 injector. Look for chafing, melted wires, or loose connections at the valve cover pass-through connector.

3. 3

   Measure the resistance of the Cylinder 2 injector solenoid to verify if it is shorted or open.

4. 4

   Use the diagnostic tool to perform a cylinder cut-out test to confirm if Cylinder 2 is contributing to engine power.

1. 1

   Disconnect battery

   Disconnect the machine's battery to prevent electrical shorts.

2. 2

   Remove valve cover

   Remove the engine valve cover / rocker cover to access the injectors.

3. 3

   Disconnect wiring

   Disconnect the injector wiring harness support and electrical connections from the Cylinder 2 injector.

4. 4

   Remove fuel line

   Remove the high-pressure fuel manifold/line connected to Cylinder 2. Note: OEM service manuals explicitly state that disassembled high-pressure fuel manifolds must not be reused and must be replaced with new ones to prevent leaks.

5. 5

   Remove hold-down

   Remove the injector hold-down fastening screws/nuts.

6. 6

   Extract injector

   Use an OEM injector puller (e.g., tool 99342101 for NEF engines) to extract the injector from the cylinder head.

7. 7

   Clean bore

   Clean the injector bore thoroughly, ensuring the old copper crush washer is removed.

8. 8

   Install new injector

   Install the new crush washer onto the new injector nozzle and seat the injector into the cylinder head.

9. 9

   Torque nut

   Torque the hold-down nut to OEM specifications (e.g., 28 N·m or 21 lb-ft for specific FPT engines).

10. 10

    Install new fuel line

    Install a new high-pressure fuel line and tighten the fittings.

11. 11

    Reassemble

    Reconnect the injector wiring harness and reassemble the valve cover.

12. 12

    Finalize and program

    Reconnect the battery, bleed the fuel system, and use the CNH diagnostic tool to program the new injector's trim code (IQA code) into the ECM.