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. J1939 is a high-speed twisted pair 250K data link with one 120 ohm resistor at each end of the link. The Hybrid Control Module (HCM) is connected to the J1939 data link at the 38-Way Connector. This link is used to transmit or receive operation information from other modules on the network like the Transmission Electronic Control Unit (TECU) or Electronic Control Unit (ECU).
Fault Code 59 – J1939 Communication Link (HCM) 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 in Product Diagnostic Mode (PDM) and occurs when the HCM loses communication with any other module on the J1939 Data Link for 3
- FMI 9 is set when the HCM loses communication with all modules on the J1939 data link for 30 consecutive messages or greater.
Fallback When Fault Code 59 is set the following conditions occur:
- Amber “Check Hybrid” and red “Stop Hybrid” lights do not display, since the lights are driven over the J1939 Data Link.
- Fault is stored in HCM memory.
- Operation mode changes to “AutoShift Only” mode.
- If the fault sets at power up, the engine will not crank.
- If the fault sets while driving, the vehicle will shift, however; when the vehicle stops the clutch opens and remains open.
- Electric Motor/Generator Assist and Regeneration are disabled; however, the high-voltage relays remain powered.
- Red “Service” light and an “F” flashing in the gear display may appear due to the Active fault code 24, 35, or 36.
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: