Massey Ferguson E677.03 – Transmission/Chassis Controller: Starter Relay Low Voltage

Starter relay normal or short-circuited to +12 V / Voltage below normal. The control unit is detecting insufficient voltage on the starter relay circuit, an open circuit, or a short to power, preventing the starter motor from receiving the necessary 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
• 5400 Series
• 5600 / 5700 Series
• 6400 / 6600 / 6700 Series
• 7400 Series
• 7600 Series
• 7700 Series
• 8400 / 8600 / 8700 Series

1. 1

   Verify battery voltage is above 12V. Check battery terminals and chassis ground connections for corrosion, as a severe voltage drop during cranking can trigger this code.

2. 2

   Turn the key and listen for a rapid clicking sound. If heard, the starter relay or pull-in winding is working, but main contacts cannot pass enough power.

3. 3

   Locate the starter relay (usually a 70-amp relay in the fuse/relay panel) and check the socket for melted plastic or corroded pins.

4. 4

   Measure the voltage at the starter feed stud (solenoid output) while attempting to crank. Good input voltage but poor output indicates burnt or pitted internal copper contacts in the solenoid.

5. 5

   Check the wiring harness between the ignition switch, the relay, and the starter solenoid for rub points that could cause a short to ground or a short to +12V.

1. 1

   Disconnect power

   Disconnect the negative battery cable before working on the starting circuit.

2. 2

   Replace the starter relay

   Locate the 4-pin or 5-pin starter relay in the fuse box. Pull the old relay out, apply a small amount of dielectric grease to the pins of the new relay, and plug it in. This is the most common fix.

3. 3

   Inspect the starter solenoid

   If the relay does not resolve the issue, the fault is likely at the starter solenoid. Remove the starter motor if access is tight (on 6400 and 7600 series, it sits behind the exhaust manifold).

4. 4

   Rebuild or replace solenoid

   Open the solenoid housing. If the heavy-duty copper contacts are pitted and burned, install a solenoid repair kit (new contacts and plunger).

5. 5

   Reassemble and clear codes

   Reinstall the starter, reconnect the battery, and use a diagnostic tool (like AGCO EDT or Jaltest) to clear the E677.03 fault code. Cycle the ignition to ensure the tractor cranks smoothly and the code does not return.