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. The Transmission Electronic Control Unit (TECU) is mounted to the transmission and contains the software to control the transmission operation; however, the Hybrid Control Module (HCM) controls the operation of the TECU during normal hybrid mode operation. The HCM main battery power is a fused 12-volt feed that runs through the HCM 38-Way Vehicle Connector with the main ground wire returning to the battery negative terminal.
Fault Code 33 – Low Battery Voltage (TECU) Detection
The following preconditions must be met before the system detects the fault:
- TECU ignition voltage is greater than 7 volts and less than 16 volts.
Conditions to Set Fault Code Active
- FMI 4 is set when the TECU battery voltage drops below 7 volts for more than 1 second.
Fallback When Fault Code 33 is set the following conditions occur:
- Fault is stored in TECU memory.
- No lights are illuminated on the Push Button.
- If this fault occurs prior to power up, the vehicle will not crank.
- If this fault occurs while driving, the vehicle maintains current gear. Clutch opens when the vehicle stops.
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 4
- Power supply to TECU
- Low batteries or bad main power connection
- Charging system