Eaton Fuller Hybrid Transmission Fault Code 54 – DC/DC Converter Output Voltage
Fault code for Eaton Hybrid Drive Systems models (MY08) EH-8E306A-U, EH-8E306A-UPG, EH-8E306A-UP, EH-8E306A-CD, EH-8E306A-T, EH-6E606B-CD, (MY09) EH-8E406A-U/P, EH-8E406A-UP, EH-8E406A-UPG, EH-8E406A-CD, EH-8E406A-CDG, EH-8E406A-CDR, EH-8E406A-T, EH-6E706B-CD, EH-6E706B-P and EH-6E706B-UPG. Read below to learn how to test, clear and fix fault code errors for your Freightliner, Mack, Peterbilt, Kenworth, Volvo and International truck. The DC/DC Converter is connected to the Power Electronics Carrier (PEC), which provides 340 volts DC. The voltage is reduced to 12-volts DC and maintains the 12-volt system during engine off PTO operation. The DC/DC maintains a steady 14.2 (±0.2) (MY08 Systems) or 12.6 (MY09 System) volts output and increases the amperage with vehicle demand up to 1.5 kw or 120 amps.
Fault Code 54 – DC/DC Converter Output Voltage 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 2 is set whenever DC/DC voltage feedback signal reads greater than 15 volts or less than 10 volts and ePTO mode is engaged.
- FMI 4 is set if the voltage feedback is less than 15 volts and greater than 10 volts and the difference between the voltage feedback and the vehicle battery voltage is greater than 0.5 volts for 1 second or more.
Fallback When Fault Code 54 is set the following conditions occur:
- Amber “Check Hybrid” light illuminates.
- Fault is stored in Hybrid Control Module (HCM) memory.
- High-Voltage Motor/Generator Assist is available, but at a reduced amount.
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 2
- Voltage Feedback wire from DC/DC Converter to HCM
- FMI 4
- 12-volt power cables from the 12-volt battery to the DC/DC Converter
- Power supply to HCM
Fault Code 54 – DC/DC Converter Output Voltage Test
Harness Front View
(HCM – Hybrid System Interface Connector)
Deutsch 4-way OEM connector
NOTE: Refer to the Eaton Hybrid Component and Connector Location for Connector Locations in MY08 Systems
NOTE: Refer to the Eaton Hybrid Component and Connector Location for Connector Locations in MY09 Systems.