Massey Ferguson 168.04 – Engine Control Unit (ECU): Battery Voltage Low (ECU)

Triggered when the unswitched supply voltage to the control unit drops below the minimum operating threshold (typically 7.8V to 8.5V).

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 4707
• 4708
• 4709
• 4710
• 5600 series
• 6600 series
• 8700 series

1. 1

   Check static battery voltage with a multimeter (should read 12.4V - 12.6V when the machine is off)

2. 2

   Test alternator output by starting the tractor and checking voltage at the battery terminals (should read 13.5V - 14.5V)

3. 3

   Visually inspect the battery terminals, cables, and the alternator for accumulated debris, corrosion, or physical damage

4. 4

   Check the unswitched power supply lines directly at the ECU harness for voltage drops to rule out a corroded ground or damaged power wire

1. 1

   Clean Connections

   Disconnect the battery cables (negative first). Clean the battery posts and cable terminals thoroughly with a wire brush to ensure a solid connection. Reconnect and retest.

2. 2

   Load Test the Battery

   If the connections are clean but the static voltage is low, perform a load test on the battery. If the battery fails the load test or is old/unable to hold a charge, replace it.

3. 3

   Replace the Alternator

   If the battery is good but the system voltage drops while running (or fails to reach 13.5V+), the alternator is faulty. Disconnect the battery, remove the serpentine/drive belt, disconnect the electrical connections on the rear of the alternator, and unbolt the unit. Install the new alternator and re-tension the belt.

4. 4

   Clear Codes

   Once the repair is complete and system voltage is restored, use a diagnostic service tool to clear the 000168.04 / SPN 168 FMI 4 fault code from the ECU.