Case IH 3069 – Engine Control Module (ECM) / Engine Controller: Cylinder 3 - injector cable short circuit (low side to battery)

The Engine Control Unit has detected that the low-voltage side of the wiring circuit for the fuel injector on Cylinder 3 is shorted to a battery power source.

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1. 1

   Inspect the wiring harness for Cylinder 3 for any chafing, melting, or external sources causing a short circuit to the battery

2. 2

   Use a multimeter or diagnostic tool to verify the signal at the injector connector

3. 3

   Test the injector to see if the short is internal to the injector's solenoid coil

4. 4

   Test the Engine Control Unit (ECU) for an internal short if the wiring and injector both test perfectly

1. 1

   Turn off the machine and disconnect the battery

   Turn off the machine and disconnect the battery to prevent further electrical damage.

2. 2

   Disconnect the electrical harness for Cylinder 3 fuel injector

   Locate the fuel injector for Cylinder 3 and disconnect its electrical harness.

3. 3

   Inspect the wiring harness

   Inspect the wiring harness running from the injector back to the ECM. Look for pinched wires, rubbed-through insulation, or areas where the low-side wire might be touching a 12V/24V power source.

4. 4

   Test the low-side pin for continuity to battery positive

   Using a multimeter, test the low-side pin on the harness connector for continuity to battery positive. If continuity exists, trace the harness to locate and repair the short circuit.

5. 5

   Test the internal resistance of the fuel injector coil

   If the wiring harness is intact and shows no shorts, test the internal resistance of the Cylinder 3 fuel injector coil. If the injector is internally shorted, replace the injector.

6. 6

   Reconnect harness and battery, then clear fault codes

   Reconnect the harness and battery. Clear the fault codes using a diagnostic tool.

7. 7

   Run the engine and replace ECU if necessary

   Run the engine. If code 3069 returns immediately and both the wiring and injector are confirmed good, replace the Engine Control Unit (ECU).