Eaton Fuller Hybrid Transmission Fault Code 66 – ECA Battery 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, International, and heavy-duty truck and equipment. The Electric Clutch Actuator (ECA) controls the position of the clutch assembly. The ECA has a main power 3-Way Connector that is directly connected to the 12-volt battery positive and negative terminals.
Fault Code 66 – ECA Battery 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.
- ECA ignition voltage is greater than 8.5 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 ECA battery voltage is above 17 volts for 10 MS or greater.
- FMI 4 is set when the ECA battery voltage is below 8.5 volts for 10 MS or greater.
- FMI 14 is set when the ECA battery voltage is below 8.5 volts for 10 MS or greater, but the HCM reports the battery voltage is within range.
Fallback When Fault Code 66 is set the following conditions occur:
- Red “Stop Hybrid” light illuminates.
- Fault is stored in HCM memory.
- If the fault occurs while driving, the ECA either maintains current clutch position or moves to the last position commanded by the HCM. Then the ECA holding device engages.
- If the fault occurs at power up, the vehicle will not crank.
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
- Charging System
- ECA
- FMI 4
- ECA Power Supply Harness, connections and fuse holder
- Low batteries or bad main power connection
- Charging system
- ECA
- FMI 14
- ECA Power Supply Harness, connections and fuse holder
Fault Code 66 – ECA Battery Voltage Test
Component Identification:
ECA 3-Way 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.
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