New Holland ENG 3406 – Engine Control Unit (ECU) / EDC7: ECU Power stages: Over temperature error on the Turbocharger PWM output power stage.

The engine controller has detected an excess current draw on the turbocharger wastegate signal wire. When there is a short circuit in the wiring or an internal short in the actuator itself, it pulls too much current, causing the ECU's internal H-bridge/power stage to overheat and log this error.

• T5.95
• T5.105
• T5.115
• T6
• T7
• T8
• T9
• MXM
• TM
• W50C ZB
• W60C ZB
• W70C HS
• W70C
• W80C HS
• W80C
• SP280
• SP480
• 580N T4
• 590SN T4
• L170
• L175
• LS170

1. 1

   Connect the Electronic Service Tool (EST) to verify fault code 3406 is active and ensure there are no other codes for high battery voltage or high fluid temperatures.

2. 2

   Turn the key switch OFF and visually inspect the engine wiring harness from the ECU to the turbocharger wastegate actuator and EGR valve for damaged insulation, corrosion, abrasion, or pinched wires.

3. 3

   Disconnect the ECU and wastegate actuator connectors, then measure the resistance of the PWM signal wires to chassis ground (should be greater than 20,000 ohms).

4. 4

   Wiggle the harness during the resistance measurement to reveal any intermittent short circuits (a reading of less than 10 ohms indicates a short to ground).

1. 1

   Repair Wiring

   If the multimeter test reveals a short to ground (resistance < 10 ohms), trace the harness to locate the chafe or pinch point. Repair the damaged wire or replace the engine wiring harness section as required.

2. 2

   Replace the Actuator/Valve

   If the wiring harness and connectors test perfectly fine, the excess current draw is being caused by an internal short inside the turbocharger wastegate actuator (electric valve) or the EGR valve. Replace the faulty actuator/valve.

3. 3

   Replace the ECU

   If the wiring is intact and the actuator has been replaced but the fault code immediately returns, the excess current draw has permanently damaged the ECU's internal PWM power stage. The Engine ECU must be replaced and reprogrammed.

4. 4

   Clear Codes

   Reconnect all components, turn the key switch ON, and use the EST to clear the fault codes. Run the engine to confirm the elimination of the fault.