Massey Ferguson 168.03 – ECU / SSU / Transmission Controller: Battery Voltage High (ECU) / Battery voltage sensor, voltage above normal.

The control unit is detecting that the unswitched supply voltage coming from the battery/charging system is exceeding the maximum safe threshold. On a standard 12V system, this typically means the alternator is overcharging (e.g., spiking above 15V). If left unaddressed, this over-voltage condition can damage the electronic control modules.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 7600 Series

1. 1

   Inspect the area around the batteries and the alternator for any obvious signs of physical damage, loose cables, or accumulated debris that could cause grounding issues or shorts.

2. 2

   Use a digital multimeter to check the resting battery voltage with the engine off.

3. 3

   Start the tractor and measure the voltage at the battery terminals. If the voltage climbs above the normal charging threshold (typically >14.5V on a 12V system), the alternator's internal voltage regulator has failed and is overcharging the system.

4. 4

   Check the wiring harness connecting the alternator, battery, and ECU to ensure there are no shorts to another power source.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable to prevent electrical shorts during the repair.

2. 2

   Remove the Alternator

   Relieve tension on the serpentine/drive belt and remove it from the alternator pulley. Disconnect the electrical connectors from the rear of the alternator, then remove the mounting bolts to extract the faulty unit.

3. 3

   Install the New Alternator

   Mount the replacement alternator and torque the bolts to OEM specifications. Reconnect the electrical terminals securely.

4. 4

   Reinstall the Belt

   Route the drive belt back over the pulleys and restore proper tension.

5. 5

   Clean Battery Terminals

   Ensure the battery posts and cable clamps are free of corrosion to guarantee a clean circuit.

6. 6

   Test the System

   Reconnect the negative battery cable. Start the tractor and use a multimeter to verify that the charging voltage is now stable and within the normal operating range.

7. 7

   Clear Codes

   Use a diagnostic service tool to clear the 000168.03 fault code from the ECU and verify that it does not return during a test run.