New Holland 3041 – ECU: HS Power Stage Cold Start Heater Relay - Source Low

The Engine Control Unit (ECU) has detected a low voltage condition in the circuit supplying power to the cold start heater relay (the high-side power stage). This low source signal prevents the relay from engaging and activating the grid heater, which is necessary to warm incoming air during cold starts and aid in combustion.

• T7 Series
• T8 Series
• L Series
• C Series
• TS-A Series
• TS115A
• L160
• L170
• C175
• C185
• C190
• LS180.B

1. 1

   Check for other electrical or sensor-related fault codes that could indicate a systemic issue

2. 2

   Verify the grid heater function is enabled in the tractor's configuration menu (e.g., H3 menu on TS115A models)

3. 3

   Inspect the main fuse box for blown fuses related to the engine controller or cold start system

4. 4

   Inspect the cold start/grid heater relay for visible damage, corrosion, burn marks, or cracks in the housing

5. 5

   Listen for an audible click from the grid heater relay when the ignition key is turned to 'on' in cold conditions

6. 6

   Test the relay circuit by probing the power supply pin at the relay socket for battery voltage with the key on

7. 7

   Inspect the wiring harness for the grid heater relay for any signs of damage, chafing, or loose connections

8. 8

   Check for approximately 12V at the grid heater power terminal when the ignition is on and the cold start light is illuminated

9. 9

   Test the grid heater element resistance between the power terminal and a good ground (should be close to 0 ohms)

1. 1

   Ensure safety

   Disconnect the battery before performing any electrical repairs.

2. 2

   Locate components

   Identify the location of the grid heater, the grid heater relay, and the relevant fuses. The relay is often in a fuse/relay box in the engine compartment.

3. 3

   Address simple fixes

   Replace any blown fuses and clean any corroded terminals on the relay and its socket.

4. 4

   Test and replace the relay

   If the relay does not click or fails a swap test with an identical relay, replace it with a new one.

5. 5

   Inspect and repair wiring

   If the relay is functional but the source low condition persists, thoroughly inspect the wiring harness between the fuse box, the relay, and the ECU. Repair or replace damaged sections (e.g., grid heater relay wiring harness).

6. 6

   Replace the grid heater

   If diagnostics show the grid heater element itself has high or infinite resistance (open circuit), replace the grid heater element.

7. 7

   Verify repair

   Reconnect the battery, clear any fault codes using a diagnostic tool, and attempt a cold start to ensure the system is functioning correctly.