Massey Ferguson E168.03 – AGCO SISU POWER EEM3 or EEM4 (Engine Control Unit): Battery voltage sensor, voltage above normal

The supply voltage being fed to the engine controller is exceeding the normal operating range. Depending on the specific system voltage, this triggers when the voltage is >17V on a 12V system or >32V to >36V on a 24V system.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 5400 Series
• 5700SL Series
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 6000 Series
• 7000 Series
• 7722
• 8000 Series

1. 1

   Measure the charging voltage at the battery while the engine is running to see if the alternator is overcharging the system

2. 2

   Ensure the battery itself is not defective and is capable of regulating the charge

3. 3

   Check the wiring path from the battery to the EEM3/EEM4 ECU for any short circuits to a higher voltage source

4. 4

   Verify the actual voltage reaching the ECU pins to rule out a harness issue

1. 1

   Test Charging Output

   Start the engine and use a multimeter to measure the voltage across the battery terminals.

2. 2

   Address Overcharging

   If the voltage is excessively high (e.g., climbing past 15V on a 12V system), the alternator's internal voltage regulator has failed. You will need to replace the alternator (or the voltage regulator if serviced separately).

3. 3

   Inspect for Shorts

   If the alternator output is normal at the battery, trace the ECU power supply harness. Look for rubbed wires that might be shorting the ECU supply line to a higher voltage source. Repair any damaged wiring.

4. 4

   Test the ECU

   If the charging system is working perfectly and the wiring is intact, the ECU's internal voltage sensor may be defective. The OEM manual recommends testing the system with a replacement EEM3/EEM4 controller. If the fault clears with the test ECU, the original ECU is defective and must be replaced.