Case IH 3300 – Engine Controller (EDC / Engine ECU): Cylinder 3 Specific Errors - Signal Low

Cylinder 3 injector mechanical response fault. The Engine Control Unit (ECU) has detected a low signal from the fuel injector on cylinder 3. This is typically caused by a short circuit in the injector cable (low side to battery or high side to ground), faulty solenoid windings within the injector itself (shorted or grounded), or a damaged wiring harness.

• Magnum 235 - 340 (Series 4)
• Steiger
• Puma
• Optum
• Farmall 115U
• T8.xxx Series
• T7 Series

1. 1

   Use the Electronic Service Tool (EST) to confirm if the fault code is currently active or if it is an inactive/stored historical code.

2. 2

   Inspect the wiring harness between the Engine ECU and the cylinder 3 injector. Verify that all connectors are properly seated, undamaged, and that the connector locks are not broken.

3. 3

   Test the cylinder 3 injector wiring for a short circuit. Check for a short from the high side to either the low side or to the ground.

4. 4

   Test the cylinder 3 injector (Y-063) solenoid windings with a multimeter to see if they are internally shorted or grounded.

5. 5

   If the wiring and injector pass electrical testing, verify if the Engine ECU (A-095) has a software glitch or requires an update.

1. 1

   Repair Wiring

   If the diagnostic checks reveal chafed, melted, or damaged wiring between the ECU and the cylinder 3 injector, repair or replace the damaged section of the wiring harness. Ensure connector locks are replaced if broken.

2. 2

   Replace the Injector

   If the wiring is intact but the cylinder 3 injector solenoid windings test faulty (shorted or grounded), safely depressurize the fuel system and replace the cylinder 3 fuel injector.

3. 3

   Address the ECU

   If both the wiring and the injector are functioning correctly, the Engine ECU may be faulty or require a software re-flash via the EST.

4. 4

   Clear and Retest

   Reconnect all components, use the EST to clear the fault codes, and run the engine under load to verify that the fault code 3300 does not return and that rail pressure deviations are within spec.