Massey Ferguson 521010.04 – Engine ECU (AGCO SISU POWER EEM4): DEF Tank Heater Solenoid Valve High Amps

The system has detected an excessive current draw (high amps), indicating a short circuit to ground either in the wiring harness or internally within the DEF tank heater coolant valve solenoid coil.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 7600 Series
• 5600 Series

1. 1

   Inspect the wiring harness running from the Engine ECU to the DEF tank heater coolant valve solenoid for chafed insulation, pinched wires, or areas shorting to ground.

2. 2

   Disconnect the solenoid valve and inspect the connector pins for corrosion, moisture, or melting.

3. 3

   Using a multimeter, measure the resistance across the pins of the solenoid valve. If resistance is near zero, the coil is internally shorted.

4. 4

   With the solenoid disconnected, check for continuity between the high-side supply wire in the harness and a known good ground to test for a shorted harness.

1. 1

   Preparation

   Turn off the tractor ignition and disconnect the battery to prevent electrical spikes. Allow the engine coolant to cool down completely.

2. 2

   Locate the Valve

   Locate the DEF tank heater coolant valve solenoid, which is plumbed into the coolant lines feeding the DEF tank assembly.

3. 3

   Clamp the Lines

   Use hose pinch-off pliers to clamp the coolant hoses on both sides of the valve. This prevents excessive coolant loss and avoids the need to drain the entire cooling system.

4. 4

   Disconnect

   Unplug the electrical connector from the solenoid valve.

5. 5

   Removal

   Loosen the hose clamps securing the coolant lines to the valve and pull the hoses off. Unbolt the valve bracket from the chassis and remove the faulty valve.

6. 6

   Installation

   Mount the new solenoid valve. Reattach the coolant hoses and securely tighten the hose clamps.

7. 7

   Reconnect

   Plug the electrical connector back into the new solenoid and remove the hose pinch-off pliers.

8. 8

   Fluid Check

   Check the engine coolant level and top off if any was lost during the swap.

9. 9

   System Reset

   Reconnect the battery. Turn the ignition off for a minimum of 60 seconds, then turn it back on to perform a system reset. Alternatively, use a diagnostic tool (like Jaltest or AGCO WinEEM4) to clear the inactive fault code.

10. 10

    Test

    Run the engine, check for coolant leaks at the valve, and verify the fault code does not return.