Massey Ferguson E626 – Engine Control Unit (ECU): Inlet Air Heater Control

Triggered when there is a voltage irregularity in the grid heater circuit, which is used to warm incoming air into the intake manifold for cold-weather engine starting.

• Massey Ferguson 7600 Series
• Massey Ferguson 8600 Series (Models 8650, 8660, 8670, 8680, 8690)

1. 1

   Retrieve the specific FMI sub-code (3, 4, 5, or 6) from the diagnostic display to determine if the fault is a short to power, short to ground, or an open circuit

2. 2

   Locate the heavy-duty grid heater relay/solenoid and its associated high-amp fuse, checking for blown fuses or a relay that is stuck open/closed

3. 3

   Trace the wiring harness from the Engine ECU to the inlet air heater relay, and from the relay to the grid heater element on the intake manifold, looking for chafed wires, melted insulation, or loose terminal connections

4. 4

   Test the voltage at the grid heater control circuit while cycling the ignition to the 'ON' position to verify if the voltage matches the ECU's expected output

5. 5

   Test the grid heater element itself for continuity to ensure it hasn't burned out internally

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical shorts or accidental arcing, as the grid heater circuit carries high amperage.

2. 2

   Access the Components

   Locate the inlet air heater (grid heater) mounted on the engine air intake manifold and its control relay.

3. 3

   Repair Wiring/Relay

   If the diagnostic tests revealed a short or open circuit in the harness, repair or replace the damaged wiring section. If the relay failed the multimeter test, unbolt the electrical leads and replace the relay.

4. 4

   Replace the Heater Element

   If the grid heater element is internally shorted or open, remove the intake piping, unbolt the grid heater assembly from the manifold, and install a new unit. Ensure you use new gaskets to prevent boost leaks.

5. 5

   Reassemble and Clear Codes

   Reconnect all heavy-gauge wiring and the battery. Use a dealer diagnostic tool (like AGCO EDT) to clear the E626 fault code, or perform a standard key-cycle to see if the ECU clears the inactive code automatically.