New Holland 3168 – ECU: Fuel Filter Heater Relay - Open Load

The Engine Control Unit (ECU) has detected an open circuit in the fuel filter heater relay's electrical path. An open load condition indicates a break in the electrical circuit, preventing current from flowing to or through the relay. This can be caused by a broken wire, a loose or corroded connector, or a failed internal component within the relay itself. As a result, the fuel filter heater will not function, which may lead to fuel gelling and restricted fuel flow during cold weather operation.

• T8 Series
• T8.xxx
• T8.330
• T8.360
• T5 Series
• T5.95
• T5.105
• T5.115
• SSL with F5C engine
• CTL with F5C engine

1. 1

   Visually inspect the wiring harness and connectors leading to the primary fuel filter and the engine compartment fuse/relay box for chafed wires, broken wires, or loose connections

2. 2

   Identify the fuel filter heater relay (e.g., X216 or R-23) and its corresponding fuse in the power distribution box. Check for a blown fuse or poor contact

3. 3

   Verify if power is being sent to the relay and from the relay to the heater using a multimeter

1. 1

   Disconnect power

   Turn the ignition off and disconnect the battery before performing any electrical repairs.

2. 2

   Locate the relay

   Find the fuel filter heater relay. Depending on the model, it may be located in the fuse/relay box (often on the deaeration tank support) or require disconnecting the harness directly at the primary fuel filter.

3. 3

   Test the relay circuit wiring

   Check for continuity on the power and return wires (e.g., Green wires on circuits 6408 and 6570) between the ECU, fuse box, and relay connector. Repair any breaks or high-resistance sections in the harness.

4. 4

   Test or swap the relay

   Swap the relay with an identical non-critical relay to see if the fault follows, or bench test it with a 12V power source and multimeter. Replace the relay if it does not click or lacks continuity across the load circuit.

5. 5

   Test the heater element

   With the heater disconnected, measure resistance across its terminals. An infinite resistance reading indicates an internal open circuit, requiring replacement of the fuel filter/heater assembly.

6. 6

   Replace the faulty component

   Based on the test results, replace the faulty relay, wiring section, or fuel filter/heater assembly.

7. 7

   Clear codes and verify

   Reassemble components, reconnect the battery, start the engine, and use a diagnostic tool to clear fault code 3168. Operate the machine (ideally in cold conditions) to ensure the code does not return.