Eaton Fuller Hybrid Transmission Fault Code 109 – High Voltage Battery 2 Control Unit Power Supply
Fault code for Eaton Hybrid Drive Systems models (MY08) EH-8E306A-U, EH-8E306A-UPG, EH-8E306A-UP, EH-8E306A-CD, EH-8E306A-T and EH-6E606B-CD. Read below to learn how to test, clear and fix fault code errors for your Freightliner, Mack, Peterbilt, Kenworth, Volvo, International, and heavy-duty truck and equipment. The high-voltage batteries are 172 volts each connected in series to produce 340 volts DC. The Battery Control Unit located in the Relay Box receives 12-volt ignition power and ground from the Inverter.
Fault Code 109 – High Voltage Battery 2 Control Unit Power Supply Detection
The following preconditions must be met before the system detects the fault:
- Hybrid Control Module (HCM) ignition voltage is greater than 7 volts and less than 16 volts.
Note: When troubleshooting an Inactive code refer to the Product Diagnostic Mode (PDM)
Conditions to Set Fault Code Active
- FMI 3 is set when the BCU detects the ignition voltage is greater than 16 volts for 1 second.
FMI 4 is set when the BCU detects the ignition voltage is less than 7 volts for 1 second.
Fallback When Fault Code 109 is set the following conditions occur:
- Amber “Check Hybrid” light illuminates.
- Fault is stored in Hybrid Control Module (HCM) memory.
- Inverter shuts high-voltage system off.
- HCM continues to control the hybrid vehicle in a diesel-only mode.
- Transmission defaults start gear to 1st.
Conditions to Set Fault Code Inactive
Only Inactive faults can be cleared from the Transmission Electronic Control Unit (TECU) or HCM history using ServiceRanger. The TECU automatically clears the faults from history after 200 hours and the HCM automatically clears the faults from history after the fault has been Inactive for 200 hours.
This fault code can be caused by any of the following:
- FMI 3
- FMI 4
- Charging system PEC Low-voltage harness from Inverter to PEC
- Low-voltage harness from the HCM to Inverter
Fault Code 109 – High Voltage Battery 2 Control Unit Power Supply Test
Harness Front View
(HCM – Hybrid System Interface Connector)
Delphi 56-Way Mating Connector View
(Inverter – Low Voltage Connector)
Deutsch 19 – Way Mating Connector View
(PEC – Low Voltage Connector)