Massey Ferguson 977.06 – Engine Control Unit (ECU) / AGCO SISU POWER EEM4: Engine Cooling Fan Speed Solenoid Issue

The system has detected that the fan control output current is above normal. This typically means there is a short circuit to ground in the wiring or an internal short circuit within the fan control solenoid itself.

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724

1. 1

   Save the error log, erase it using a diagnostic service tool, and perform a system reset by turning the ignition off for a minimum of 60 seconds, then turn it back on. See if the fault returns.

2. 2

   Inspect the wiring harness between the EEM4 ECU and the cooling fan for chafing, melting, or pinched wires that could cause a short circuit to ground.

3. 3

   Disconnect the fan control solenoid and test its internal resistance with a multimeter. A reading near zero ohms indicates the solenoid is internally shorted.

4. 4

   Check the ECU output pins for the fan control circuit to ensure there is no short at the connector itself.

1. 1

   Disconnect battery

   Turn off the tractor ignition and disconnect the battery to prevent electrical damage during the repair.

2. 2

   Locate solenoid

   Locate the engine cooling fan speed solenoid, which is typically integrated into or mounted on the viscous fan clutch assembly at the front of the engine.

3. 3

   Repair wiring

   If the diagnostic checks revealed a wiring issue, repair the damaged section of the harness or replace the affected wiring loom. Ensure all wires are properly insulated and routed away from high-heat or moving engine components.

4. 4

   Replace solenoid or fan clutch

   If the solenoid tested faulty (internally shorted), replace the cooling fan speed solenoid. On many of these models, the solenoid is integrated into the electronic viscous fan clutch, requiring the replacement of the entire viscous fan clutch assembly.

5. 5

   Reconnect electrical connectors

   Reconnect the electrical connectors, ensuring they are clean, dry, and securely seated.

6. 6

   Reconnect battery

   Reconnect the battery.

7. 7

   Clear fault codes

   Connect a diagnostic tool (such as the AGCO Electronic Diagnostic Tool) to clear the fault codes from the EEM4 ECU.

8. 8

   Verify repair

   Start the engine, allow it to reach operating temperature, and monitor the fan operation to verify the repair and ensure the 000977.06 code does not return.