Massey Ferguson 168 – Engine Control Unit (ECU): Battery Voltage High

The electrical charging voltage has exceeded the safe operational threshold. For a standard 12V system, this code typically logs when the voltage spikes above 16.5V-17.0V. For 24V systems, it logs if voltage exceeds 32.0V-36.0V.

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724
• 6600 Series
• 7600 Series
• 7700 Series
• 8600 Series
• 8700 Series
• 9695
• 9795

1. 1

   Immediate Action: Stop machine operations immediately. Running the tractor with an overcharging alternator can fry the ECU, TCU, dash cluster, and other sensitive electronics.

2. 2

   Multimeter Voltage Test: With the engine off, check the battery voltage across the terminals (should be around 12.6V). Start the engine and check the voltage again. A healthy charging system should read between 13.5V and 14.5V. If it reads above 15V (and especially if it climbs toward 17V), the alternator is overcharging.

3. 3

   External Factors: Verify that no external battery charger, jump pack, or welding equipment was recently connected to the machine while the ECU was powered on, as this can trigger a false code.

4. 4

   Wiring & Grounds: Inspect the wiring harness between the alternator, battery, and ECU. Look for shorts to a higher voltage source or heavily corroded ground connections that might cause the voltage regulator to misread the system voltage.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent any further electrical damage or accidental shorts during the repair.

2. 2

   Inspect the Alternator/Regulator

   The most common cause of this fault is a failed voltage regulator. On modern Massey Ferguson tractors, the voltage regulator is internal to the alternator.

3. 3

   Replace the Alternator

   If the multimeter test confirmed an overcharge condition, remove the serpentine/V-belt tensioner to slip the belt off the alternator pulley. Disconnect the electrical connectors at the rear of the alternator, unbolt the mounting hardware, and remove the faulty unit.

4. 4

   Install the New Unit

   Mount the replacement alternator, torque the bolts to OEM spec, reconnect the electrical harness, and reinstall the drive belt.

5. 5

   Battery Maintenance

   Inspect the battery for signs of boiling or acid venting (a common side effect of overcharging). Clean the terminals and replace the battery if it sustained damage.

6. 6

   Re-test and Clear Codes

   Reconnect the negative battery cable. Start the tractor and verify with a multimeter that the charging voltage is now stable at ~14.0V. Use a diagnostic scan tool to clear the 000168.00 / SPN 168 FMI 0 fault code from the ECU.