Massey Ferguson E677.06 – ECU: Starter Relay Low Voltage

Voltage on the low side of the starter relay circuit is below normal operating parameters. This condition usually points to a voltage drop caused by high resistance, a failing relay, corroded connections, or a weak battery that collapses under load, preventing the starter solenoid from receiving enough current to crank the engine.

• 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 to 7726

1. 1

   Battery Test: Check the battery's resting voltage and cranking voltage. A rapid clicking sound with a dimming dash often means the battery voltage is collapsing under load.

2. 2

   Fuse Inspection: Locate the main fuse panel and check the 5A fuse designated for the Starter Relay.

3. 3

   Voltage Drop Tests: Test the positive cable voltage drop to the starter main terminal and the earth strap voltage drop to the starter casing.

4. 4

   Relay Resistance Test: Remove the starter relay and use a multimeter set to resistance (Ohms) mode. Measure the resistance across the relay terminals. If the resistance is out of specification (too high or infinite), the relay's internal contacts are burnt or failing.

5. 5

   Trigger Wire Check: Check the solenoid trigger wire voltage when the ignition key is turned to the START position.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to ensure safety while working on the electrical system.

2. 2

   Locate the Relay

   Access the main fuse/relay box (location varies by cab layout, often behind the steering/meter panel or side console). Locate the starter relay.

3. 3

   Remove and Inspect

   Pull the faulty starter relay. Inspect the socket for melted plastic, burnt contacts, or corrosion. Clean the socket terminals with contact cleaner if necessary.

4. 4

   Install New Relay

   Plug the replacement starter relay firmly into the socket.

5. 5

   Reassemble and Reconnect

   Reinstall any removed panels and reconnect the negative battery cable.

6. 6

   Clear Codes and Test

   Start the engine. You may need to operate the tractor for a few driving cycles to ensure the code clears, or use a diagnostic tool (like Jaltest) to manually clear the inactive fault code from the ECU.