Massey Ferguson 677.06 – Engine Control Unit (ECU): Starter Relay Low Voltage

The control module is detecting that the voltage on the starter relay circuit has dropped below the normal operating threshold. This typically results in a 'no-crank' or 'clicking' condition where the starter motor does not receive enough power to engage the flywheel and turn the engine over.

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

1. 1

   Perform a battery load test to ensure it has the amperage to engage the solenoid and starter simultaneously

2. 2

   Visually inspect battery cables and earth/ground paths for corrosion, ensuring they are clean and tightly attached

3. 3

   Perform a voltage drop test at the starter end of the cable (at the 'B' terminal on the starter solenoid) while the ignition key is turned to the 'Start' position

4. 4

   Check the solenoid trigger voltage on key start to determine if the starter relay is failing or if the solenoid's internal contacts are burnt

1. 1

   Disconnect Power

   Always disconnect the negative battery cable before working on the electrical system.

2. 2

   Locate the Relay

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

3. 3

   Remove the Old Relay

   Pull the faulty 4-pin starter relay straight out of its socket. Inspect the socket terminals for signs of melting, burning, or moisture intrusion.

4. 4

   Install the New Relay

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

5. 5

   Clean Connections

   While the battery is disconnected, clean the starter motor feed stud and ground connections to prevent future voltage drops.

6. 6

   Test

   Reconnect the battery and turn the key to verify the tractor cranks and the fault code clears. (Note: If the relay does not fix the issue and voltage is still dropping at the starter, the starter solenoid or the starter motor itself will need to be removed and rebuilt/replaced.)