New Holland ENG 3403 – Engine Control Unit (ECU): Start Relay - ECU Power stages: Starter Relay High Side Power Stage Over Temperature

The Engine Control Unit (ECU) has sensed that the starter is being continuously energized. As a result, the internal power stage (the driver circuit inside the ECU that controls the starter relay) has overheated.

• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• W50C
• W60C
• W70C
• W80C
• T4.75
• T4.85
• T4.95
• T4.105
• T4.115
• T5.95
• T5.105
• T5.115
• TD5 Series
• Boomer Series
• CR9060
• CR9070
• CR9090
• CX8080
• CX8090

1. 1

   Verify that the fault code is currently active

2. 2

   Check for a short circuit in the starter relay circuit (the wiring harness running between the Engine ECU and the starter relay)

3. 3

   Test the crank/starter relay to see if it is faulty or mechanically stuck in the closed/energized position

1. 1

   Inspect the Harness

   Visually and electrically inspect the wiring harness between the Engine ECU and the starter relay for shorts to ground or power. Repair any damaged wiring.

2. 2

   Test/Replace the Starter Relay

   If the wiring is intact, test the starter relay. If it is faulty, replace it with a new OEM relay.

3. 3

   Clear and Retest

   Clear the fault code and operate the machine. If the failure isn't present after a short time, no further reaction is needed.

4. 4

   Replace the ECU

   If the fault persists after verifying the wiring and replacing the starter relay, the ECU's internal power stage has suffered a permanent failure. You must replace the EDC (Engine Control Unit).