New Holland NH 3054 – Engine Control Module (ECM): LS Power stage cold start lamp - SOURCE LOW

The Engine Control Module (ECM) is detecting a short to ground or an open circuit on the low-side control wire that illuminates the cold start indicator lamp.

• T6 Series
• T7 Series
• T7.175
• T7.210
• T8 Series
• T8.350
• TN75D
• Magnum equivalents
• B-Series Backhoe Loaders
• B90B
• B115B
• Wheel Loaders
• Dozers
• D350

1. 1

   Turn the ignition key to the ON position and observe if the 'Wait-to-Start' (cold start) lamp illuminates during the initial bulb-check cycle

2. 2

   Inspect the wiring harness running from the Engine ECU to the cab/instrument cluster for chafing, pinched wires, or melted insulation

3. 3

   Verify if there are active codes for the grid heater relay itself (e.g., NH 3056, 3057, 3058, or 12B), as a short here can pull down shared reference voltages or ground paths

4. 4

   Disconnect the harness at the ECU and the instrument cluster, then measure the resistance of the cold start lamp control wire to chassis ground to check for a short circuit

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent electrical spikes during testing.

2. 2

   Isolate the Circuit

   Unplug the main harness connector at the Engine ECU and the connector at the back of the instrument cluster.

3. 3

   Trace the Short

   Using a digital multimeter, probe the specific pin for the cold start lamp on the ECU harness connector and the other lead to a known good chassis ground.

4. 4

   Repair the Wiring

   If continuity to ground is found, physically trace the wire through the firewall and cab routing. Repair any damaged, rubbed, or exposed sections of the wire using heat-shrink tubing and electrical tape.

5. 5

   Cluster Verification

   If the wire tests good (no short to ground), the fault may lie internally within the instrument cluster (a shorted LED/bulb circuit) or a failed low-side driver inside the Engine ECU.

6. 6

   Reassembly

   Reconnect the instrument cluster and ECU harnesses. Reconnect the battery.

7. 7

   Clear and Verify

   Turn the key ON, clear the inactive fault codes using a diagnostic tool, and cycle the key to verify the NH 3054 code does not return.