Case IH 3989 – Engine ECU: Aftertreatment Burner Injector 1 Short Circuit

The engine's control system has detected an electrical short (abnormally high current draw or 0 ohms of resistance) in the circuit responsible for firing Burner Injector 1.

• skid steer
• Farmall 30A
• Farmall 35A
• Farmall 30C
• Farmall 35C
• SR130
• SR160
• SR175
• SV185
• TR270
• Steiger series

1. 1

   Inspect the wiring harness running from the Engine ECU to the DPF/DOC burner assembly for melted insulation, chafing, or pinched wires that could be shorting to the chassis (ground) or another power wire.

2. 2

   Perform an injector continuity test: Disconnect the electrical connector at Burner Injector 1 and check for continuity across pin 1 and pin 2. A reading of 0 Ω (dead short) or infinite resistance (open circuit) indicates a failed internal solenoid.

3. 3

   If the injector tests good, use a multimeter to check the harness side of the connector for a short to ground or a short to battery voltage while the key is ON (engine off).

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent electrical spikes during the repair.

2. 2

   Locate the Injector

   Locate Burner Injector 1 on the exhaust aftertreatment (DPF/DOC) assembly.

3. 3

   Remove Connections

   Disconnect the electrical harness connector from the faulty burner injector.

4. 4

   Disconnect Fuel Lines

   Carefully remove the hose clips and disconnect the fuel hoses routed to the injector. Have a rag ready to catch residual fuel.

5. 5

   Remove the Injector

   Unbolt and extract the burner injector from the exhaust housing. Ensure you remove the old O-ring seals and ceramic insulating washers, as they can sometimes stick to the housing.

6. 6

   Install the New Injector

   Using a new OEM service kit, install the new burner injector. You must use the new ceramic washers, insulators, and O-ring seals provided in the kit to prevent exhaust leaks and heat transfer damage.

7. 7

   Reassemble

   Attach the new fuel hoses and secure them with the new hose clips provided in the kit. Reconnect the electrical harness.

8. 8

   Restore Power & Clear Codes

   Reconnect the battery. Connect a diagnostic scan tool (or DTC Eraser) to the machine's diagnostic port and clear the 3989 fault code from the Engine ECU memory.

9. 9

   Test Operation

   Start the engine. You may need to initiate a manual/forced DPF regeneration via the dash or diagnostic tool to verify that the burner ignites properly and the code does not return.