Case IH 3070 – Engine Control Unit (ECU): Cylinder 3 - Application Dependent / Cylinder 3 signal low / Injector, solenoid Power stage: Short circuit in the injector 3

The engine control system has detected an electrical fault on the fuel injector circuit for Cylinder 3. The system is seeing a low signal, a short circuit (either high side to ground or low side to battery), or a defective injector coil.

• Magnum 235-340 (Series 4)
• Steiger series
• Luxxum (100, 110, 120)
• Farmall series
• 580 Super N
• T8.xxx Series

1. 1

   Inspect the wiring harness between the Engine ECU and the Cylinder 3 injector for chafing, pinched wires, or a short circuit to an external source or to ground.

2. 2

   Use a diagnostic tool or oscilloscope to verify if the ECU is sending the proper injection signal to Cylinder 3.

3. 3

   Measure the resistance of the Cylinder 3 injector coil with a multimeter to determine if it is internally shorted or open.

4. 4

   If the wiring and the injector coil both test perfectly fine, verify if the defect is caused by an internal ECU hardware failure.

1. 1

   Prep the Machine

   Park the machine on a level surface, turn off the engine, and disconnect the negative battery cable to ensure safety while working on the electrical and fuel systems.

2. 2

   Gain Access

   Remove any engine cowlings, side panels, or intake piping necessary to access the engine's fuel rail and injectors.

3. 3

   Disconnect Electricals

   Carefully unplug the electrical harness connector from the Cylinder 3 fuel injector.

4. 4

   Clean the Area

   Thoroughly clean the area around the Cylinder 3 injector and fuel rail to prevent dirt from falling into the open cylinder or fuel system.

5. 5

   Remove Fuel Line

   Loosen and remove the high-pressure fuel injection line connecting the fuel rail to the Cylinder 3 injector. Cap both the rail fitting and the injector inlet immediately to prevent contamination.

6. 6

   Extract the Injector

   Remove the injector hold-down clamp or retaining bolt. Carefully pull the Cylinder 3 injector out of the cylinder head.

7. 7

   Prep the New Injector

   Lubricate the new injector O-rings. Ensure the old copper sealing washer was removed from the cylinder head and install a new copper washer on the new injector.

8. 8

   Installation

   Seat the new injector into the cylinder head. Reinstall the hold-down clamp and torque the retaining bolt to the specific OEM torque spec for your engine model.

9. 9

   Reconnect Lines & Wiring

   Reinstall the high-pressure fuel line (torque to spec) and plug the electrical connector back into the injector.

10. 10

    Finalize

    Reconnect the battery. Bleed the fuel system if required by your specific engine manual. Start the engine, check for fuel leaks, and use a diagnostic tool to clear fault code 3070.