John Deere 003361.06 – ECU: DEF Injector Circuit Current Above Normal

The Engine Control Unit (ECU) has detected that the current in the DEF dosing unit circuit is above the normal operating range, indicating a short to ground. This condition is typically caused by low resistance from an internal short circuit in the DEF injector solenoid or damaged wiring, which causes excessive electrical current draw. This fault can lead to issues with the emission control system, resulting in reduced engine performance or placing the machine into a derated mode to prevent damage and limit emissions.

• Tier 4 and newer tractors
• Tier 4 and newer loaders
• Other equipment equipped with Tier 4 and newer diesel engines utilizing an SCR system

1. 1

   Visually inspect the DEF injector and wiring harness for melted plastic, chafed wires, corrosion, or white crystalline residue.

2. 2

   Check for other fault codes using a diagnostic scanner to rule out a more widespread harness issue.

3. 3

   Disconnect the DEF injector and measure resistance across its two pins (typical reading is 2 to 10 ohms; a reading near zero indicates an internal short circuit).

4. 4

   Inspect the harness connector for damage and check for a short to ground by measuring resistance between each wire and a clean chassis ground (should be infinite/open circuit).

5. 5

   If all other possibilities are ruled out, check for an ECU malfunction, though this is rare.

1. 1

   Isolate the fault

   Based on the diagnostic checks, determine whether the short circuit is located within the DEF injector solenoid or the wiring harness.

2. 2

   Replace or repair faulty component

   Replace the DEF injector if it is internally shorted. If the wiring harness is shorted, repair the damaged section of wire or replace the harness if the damage is extensive.

3. 3

   Clean mating surfaces

   If replacing the injector, ensure the mounting surface is clean. If DEF has spilled, clean the area with distilled water to prevent corrosion.

4. 4

   Reassemble and clear codes

   Reconnect all electrical connections and use a diagnostic tool to clear the 003361.06 fault code.

5. 5

   Verify the repair

   Start the engine and allow it to run. Perform a test drive or operate the machine to ensure the fault code does not reappear.