Massey Ferguson E626.05 – Engine ECU (EEM4): Grid Heater Relay (Engine Intake Heater) - Current below normal or open circuit

The engine controller has detected an open circuit or an abnormally low current draw in the circuit that controls the engine intake grid heater relay.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 5400 Series
• 5600 Series
• 6600 Series
• 6700 Series
• 7600 Series
• 7700 Series
• 7714
• 7715
• 8600 Series

1. 1

   Check the grid heater relay (70 Amp, 4-pin) for internal failure, burnt contacts, or melted plastic.

2. 2

   Inspect the wiring harness between the EEM4 Engine ECU and the grid heater relay for broken wires, chafing, or disconnected plugs.

3. 3

   Inspect the connector pins at the relay and the ECU for corrosion, moisture, or loose fitment.

4. 4

   Test the main fuses supplying power to the grid heater circuit.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable to ensure safety while working on high-current electrical components.

2. 2

   Access the Relay

   Locate the grid heater relay. On many Massey Ferguson models, this heavy-duty relay is located near the starter motor or in the main engine fuse/relay box.

3. 3

   Test the Circuit

   Disconnect the wiring harness from the relay. Use a multimeter to test the relay coil for continuity. If the relay coil shows infinite resistance (open), the relay has failed and must be replaced.

4. 4

   Verify ECU Wiring

   If the relay tests fine, use the multimeter to check the continuity of the control wire from the ECU pin to the relay connector. Repair any broken wires in the harness.

5. 5

   Replace the Relay

   If the relay is faulty, install a new 70 Amp, 4-pin relay. Ensure the connections are tight and free of corrosion.

6. 6

   Clear Codes

   Reconnect the battery, turn on the ignition, and use a diagnostic service tool (such as the AGCO WinEEM4 Service Tool) to clear the fault code.

7. 7

   Verify Repair

   Cycle the key to verify the intake heater operates correctly during a cold start and ensure the E626.05 / SPN 626 FMI 5 code does not return.