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, International, and heavy-duty truck and equipment. The Auxiliary Power Generator (APG) is a 5kW/5kVA DC/AC Inverter connected to the high voltage DC bus of the Eaton hybrid electric vehicle system. It generates 60 Hz single-phase 120-volt AC power for utility applications.
Fault Code 123 – APG Unit 1 High Voltage Battery Detection
The following preconditions must be met before the system detects the fault:
- FMI 3, 4: APG Inverter needs to be operating.
- FMI 14: APG Inverter needs to be in pre-charge phase.
Note: When troubleshooting an Inactive code refer to the Product Diagnostic Mode (PDM)
Conditions to Set Fault Code Active
- FMI 3 is set when high voltage DC has been detected to surpass an upper limit.
- FMI 4 is set when high voltage DC has been detected to drop below a lower limit.
- FMI 14 is set when the APG cannot stabilize high voltage DC during the pre-charge phase.
Fallback When Fault Code 123 is set the following conditions occur:
- Amber “Check Hybrid” light illuminates.
- APG shuts down if operating.
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, 14
- High-Voltage DC Cable