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

Component Identification:

HCM - Hybrid System Interface Connector

Harness Front View
(HCM – Hybrid System Interface Connector)

Fuller transmission Deutsch 4-way OEM 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.

HCM DCDC converter connector location

STEP 1.Verify Active or Inactive fault code status and FMIs present.

  1. Review and follow the Warnings & Cautions.
  2.  Retrieve Active fault codes and FMIs with ServiceRanger using the 9-Way Diagnostic Connector.
  3. Key off.
    Danger: See High-Voltage Service Shutdown and Power-Up Procedures. Follow the procedures to avoid shock, burn or death from improperly handled high-voltage.
  4. Which FMIs are present?
    • If FMI 2 is listed, go to Step 2.
    • If FMI 4 is listed, go to Step 3.

STEP 2.Verify voltage from DC/DC Converter to HCM.

  1. Key off
  2. Select ePTO Mode on the Pushbutton or Shift Lever.
  3. Measure voltage at the DC/DC Converter 12-Volt Output Terminals:
    • If voltage is greater than 10 volts, repair the open or shorted harness from Pin 1 of the DC/DC Converter to Pin 19 of the HCM, then go to Step 5.
    • If voltage is less than 10 volts, replace the DC/DC Converter, then go to Step 5.

STEP 3. Verify DC/DC Converter output voltage.

  1. Key on.
  2. Connect ServiceRanger to the 9-Way Diagnostic Connector in cab.
  3. View the following Data Monitor parameters in neutral:
    • PID 121 “DC/DC Converter Output Voltage.”
    • PID 165 “Battery Potential Voltage.”
      • If voltage at the DC/DC Converter is 12–14 volts, go to Step 4.
      • If voltage is outside of range, repair the open harness or fuse in the Main Power Supply from the DC/DC Converter to the 12-Volt Battery. Go to Step 5.

STEP 4. Verify voltage of DC/DC Converter.

  1. Key on.
  2. View the following Data Monitor parameters:
    • PID 121 “DC/DC Converter Output Voltage.”
    • PID 165 “Battery Potential Voltage.”
      • If PID 165 is 0.5 volts less than PID 121, repair or replace the DC/DC Converter Power Supply Harness that powers the 12-Volt Battery System, then go to Step 5.
      • If PID 121 is 0.5 volts less than PID 165, repair the voltage feedback wire that goes from Pin 1 of the DC/DC Converter to Pin 19 of the HCM. Go to Step 5.

STEP 5. Verify repair.

  1. Key off.
  2.  Key on.
  3. Clear codes, see  Clear Inactive Faults.
  4. Reconnect all connectors and the negative battery cable.
  5. Drive the vehicle and attempt to reset the code.
  6. Check for codes, see View Active and Inactive Faults.
    • If no codes, test is complete.
    • If fault Code 54 appears, find error in testing, go to Step 1.
    • If a code other than 54 appears, see Fault Code Index List.

Any transmission part you need we have it! Same day shipping available, worldwide.

NEED FREE SUPPORT FROM ONE OF OUR EXPERTS?

CALL NOW
EMAIL US