Massey Ferguson E677.05 – Engine ECU (AGCO SISU POWER EEM4): Starter Relay Low Voltage

The engine management system has detected an open circuit, low voltage, or insufficient current draw on the low side of the starter relay circuit. When this occurs, the starter motor cannot receive the signal to engage, resulting in a 'no crank' condition (often just a clicking sound).

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

1. 1

   Battery & Ground Check: Verify battery voltage is sufficient and inspect the cab-to-starter and battery-to-starter negative cable harnesses for clean, tight connections.

2. 2

   Relay Circuit Test: Test the starter relay circuit between the Engine ECU and the relay block.

3. 3

   Inspect ECU Connectors: Check the 94-pin/96-pin vehicle connector at the Engine ECU (specifically Pin 183, which controls the start relay) for pushed-out pins, moisture, or corrosion.

4. 4

   Test the Relay: Swap the starter relay with a known good relay of the same amperage (70-amp, 4-pin) in the fuse box to see if the fault clears.

1. 1

   Disconnect Power

   Open the vehicle's main battery isolator switch or disconnect the negative battery terminal. Note: Never connect or disconnect the ECU vehicle connectors while the power supply lines are live, as sparking can permanently damage the ECU pins.

2. 2

   Locate the Relay

   Access the main fuse and relay panel (location varies by cab model, refer to the operator's manual).

3. 3

   Remove the Faulty Relay

   Pull the 4-pin starter relay straight out. Inspect the socket terminals for signs of burning, pitting, or moisture intrusion (which are the biggest killers of agricultural relays).

4. 4

   Install the New Relay

   Plug the new 70-amp heavy-duty relay directly into the socket. No wire splicing is required.

5. 5

   System Reset

   Reconnect the battery/main switch. Turn the ignition on and wait for a minimum of 60 seconds, then turn it off, and back on to allow the EEM4 system to reset.

6. 6

   Test

   Attempt to crank the tractor to verify the E677.05 code has moved to an inactive state and the engine starts.