John Deere 003473.04 – ECU: Exhaust Throttle Flap Actuator Signal Issue

The Engine Control Unit (ECU) has detected that the signal voltage from the exhaust throttle flap actuator is below the normal operational threshold (out of range low). This indicates a potential short to ground in the electrical circuit or an internal failure of the actuator itself. The exhaust throttle flap manages exhaust temperatures for diesel particulate filter (DPF) regeneration; when this fault is active, the ECU may derate engine power and disable the automatic exhaust filter cleaning process to protect the engine and aftertreatment system.

• 650K Crawler Dozer
• 550K Crawler Dozer
• 450K Crawler Dozer
• Machines with 4.5L PowerTech Engines
• Machines with 6.8L PowerTech Engines

1. 1

   Visually inspect the exhaust throttle actuator, electrical connector, and wiring harness for damage, corrosion, or loose connections

2. 2

   Manually inspect the exhaust throttle flap to ensure it moves freely and is not seized or obstructed by soot buildup

3. 3

   Verify the actuator is receiving correct voltage and has a solid ground connection at the harness connector

4. 4

   Check the signal wire between the actuator and the ECU for shorts to ground (resistance to ground should typically be greater than 5,000 ohms)

5. 5

   If the actuator communicates via CAN bus, check for correct CAN Hi and Lo voltages (typically around 2.5 volts each)

1. 1

   Retrieve and Document Fault Codes

   Use a diagnostic scanner to confirm that 003473.04 is the active fault code. Note any other active codes.

2. 2

   Perform Preliminary Checks

   Complete the diagnostic checks listed in the section above.

3. 3

   Isolate the Fault

   If the throttle flap is stuck, remove it and clean or replace it as necessary. If wiring issues are found (e.g., corrosion, damage, short to ground), repair or replace the affected section of the harness.

4. 4

   Test the Actuator

   If the wiring and throttle flap are in good condition, the fault likely lies with the actuator itself. It is common for these actuators to fail electronically.

5. 5

   Component Replacement

   If the actuator is determined to be faulty, it must be replaced.

6. 6

   Clear Fault Codes and Verify Repair

   After replacing the part, clear the fault codes from the ECU and operate the machine to ensure the code does not return. Some systems may require a calibration or 'learn' procedure for the new actuator, which may require a dealer-level diagnostic tool.