New Holland ENG 3258 – Engine Control Unit (ECU): Starter Relay: High Side Power - Short Circuit to Battery

The Engine Control Unit (ECU) controls the starter relay using a low-side and high-side driver circuit. If the ECU detects that the high-side driver circuit (which supplies voltage to the starter control relay) is short-circuited to battery voltage, it will log this fault. This means that the wiring harness, the relay actuator, or the connector is receiving unintended battery voltage, which typically results in a "no crank / no start" condition to protect the system.

• L216
• L220
• L223
• L225
• L228
• C190
• C227
• C232
• Super Boom L180
• W50C
• W60C
• W70C
• W80C
• B110B
• T7 Series
• T7.175
• T7.190
• T7.210
• T8 Series
• Workmaster 50
• Boomer Series

1. 1

   Always disconnect the battery before testing or swapping relays to prevent further electrical shorts.

2. 2

   Locate the starter relay in the main fuse/relay box. Remove it and inspect the socket for melted plastic, burnt contacts, or heavy corrosion.

3. 3

   Using a multimeter, test the wiring harness between the ECU and the starter relay socket. Check for continuity to the positive battery terminal with the key off to confirm if the short is in the wiring harness.

4. 4

   If the wiring harness does not show a short to battery voltage, the internal electromagnetic switch inside the relay itself has likely failed and shorted out.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable.

2. 2

   Locate the Relay

   Access the main electrical distribution panel or fuse box (location varies by model; often in the cab console or engine bay).

3. 3

   Remove the Faulty Relay

   Pull the starter relay straight out of its socket.

4. 4

   Clean the Socket

   Clean any dirt, moisture, or corrosion from the relay socket using electrical contact cleaner.

5. 5

   Repair Wiring (If Applicable)

   If your diagnostic checks revealed a short in the wiring harness, trace the wire from the relay socket back to the ECU and repair the chafed or melted section of the wire.

6. 6

   Install New Relay

   If the wiring is intact, plug a new OEM starter relay directly into the socket. Ensure it is seated firmly.

7. 7

   Test the System

   Reconnect the negative battery cable. Turn the ignition key to verify that the engine cranks, starts, and the ENG 3258 fault code clears from the dash display.