Case IH 3312 – EDC: Cylinder 6 Specific Errors - Signal Low

This fault indicates a low voltage or short-to-ground condition on the electrical circuit for the fuel injector on Cylinder 6. The system detects that the electrical signal returning from the Cylinder 6 injector is below the expected threshold, which prevents the injector from firing correctly.

• Case IH equipment utilizing CNH EDC Tier 3 and Tier 4a engines (8.3L, 9L, 15L)
• Case IH Magnum 235 - 340 (Series 4)
• Case IH Puma series

1. 1

   Inspect the engine wiring harness between the Engine ECU and the Cylinder 6 injector for any visible damage, chafing, or pinched wires that could cause a short to ground.

2. 2

   Disconnect the Cylinder 6 injector connector and inspect the pins for corrosion, moisture, or bent terminals.

3. 3

   Use a multimeter to test the injector circuit wiring for continuity and check for a short to ground.

4. 4

   Measure the resistance (ohms) of the Cylinder 6 injector solenoid itself to verify it is within OEM specifications. An internally shorted injector solenoid will pull the signal voltage low and trigger this code.

1. 1

   Prepare machine

   Turn off the machine, remove the key, and disconnect the battery to ensure safety while working on the engine's electrical and fuel systems.

2. 2

   Locate injector

   Locate the Cylinder 6 fuel injector and its corresponding electrical connector.

3. 3

   Disconnect harness

   Disconnect the wiring harness from the injector.

4. 4

   Repair wiring harness

   If the harness is faulty: Repair the shorted section of the wiring harness or splice in a new injector connector pigtail.

5. 5

   Clean area

   If the injector is faulty: Clean the area around the injector to prevent debris from entering the engine.

6. 6

   Remove fuel pipe

   Remove the high-pressure fuel injection pipe/tube connected to Cylinder 6.

7. 7

   Extract injector

   Remove the injector hold-down clamp and carefully extract the faulty Cylinder 6 injector.

8. 8

   Install new injector

   Install the new OEM injector, ensuring all single-use seals (like O-rings or banjo connector seals) are replaced.

9. 9

   Reinstall fuel line

   Reinstall the high-pressure fuel line and torque all fittings to OEM specifications.

10. 10

    Reconnect electrical connector

    Reconnect the electrical connector to the injector.

11. 11

    Verify repair

    Reconnect the battery, clear the fault codes using a diagnostic tool, and run the engine to verify the repair and check for any fuel leaks.