Massey Ferguson E1077.03 – EEM4: MPROP control, Metering unit AD-channel voltage above normal

The measured voltage on the control circuit for the fuel metering solenoid (MPROP) is higher than the expected normal range, which typically points to an open circuit, a short to a high-voltage source, or an internal failure of the solenoid itself.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 6465
• 6470
• 6475
• 6480
• 7480
• 7700 Series

1. 1

   Inspect the wiring harness and connectors between the EEM4 engine controller and the MPROP solenoid on the high-pressure fuel pump for chafed wires, disconnected plugs, or corrosion.

2. 2

   Test the AD-channel voltage and the resistance of the MPROP solenoid using a multimeter to determine if the solenoid has failed internally.

3. 3

   Verify that the mechanical fuel lift pump is supplying adequate low-pressure fuel to the high-pressure pump.

4. 4

   Check for air intrusion in the fuel lines (temporarily install clear plastic fuel lines to observe if air bubbles are reaching the injection pump).

5. 5

   Check and replace the fuel filters with genuine OEM filters to rule out severe fuel restrictions causing pump starvation.

1. 1

   Confirm fault code

   Connect a compatible diagnostic tool (such as the AGCO EDT) to the tractor to confirm E1077.03 is the primary active code.

2. 2

   Inspect and clean connector

   Disconnect the electrical connector at the fuel metering unit (MPROP) on the high-pressure pump. Clean the contacts with electrical contact cleaner and check for pushed-back pins.

3. 3

   Inspect and repair wiring

   Trace the wiring harness back to the EEM4 controller. Repair any damaged sections of the harness that may be causing the 'voltage above normal' condition.

4. 4

   Replace fuel metering unit

   If the wiring is intact, the MPROP solenoid itself is likely faulty. Depending on the exact pump model, replace the fuel metering unit (ZME/MPROP valve).

5. 5

   Replace high-pressure fuel pump

   If the metering unit cannot be serviced separately, or if the high-pressure pump has suffered internal mechanical failure (a common issue noted when this code persists under load), the entire high-pressure fuel injection pump must be replaced or sent to a certified diesel shop for remanufacturing.

6. 6

   Bleed fuel system

   After replacing the solenoid or pump, bleed the fuel system completely to remove all air.

7. 7

   Clear codes and test

   Clear the fault codes via the diagnostic tool and test run the tractor under load to ensure the E1077.03 code does not return and that the engine does not derate.