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 Motor/Generator Temperature Sensor is a thermistor located inside the Motor/Generator that changes in value based on the temperature. The Inverter supplies a 5-volt reference voltage to the sensor and measures the volt drop in the circuit. When the Motor/Generator temperature is warm, the sensor resistance is low and the Inverter detects low-voltage (0.2 volts equals 536 °F [280 °C]). When the Motor/Generator is cold the sensor resistance is high and the Inverter detects high voltage (4.1 volts equals or 32 °F [0 °C]).
Fault Code 2 – Motor / Generator Temperature Sensor Detection
The following preconditions must be met before the system detects the fault:
- Inverter ignition voltage is greater than 7 volts and less than 16 volts.
Conditions to Set Fault Code Active
Conditions to Set Fault:
• FMI 3 is set when the sensor voltage is greater than 4.1 volts for 10 seconds, while the Inverter temperature is over 35 °C or 95 °F, or if the sensor output voltage is less than 0.2 volts for 10 seconds.
Fallback When Fault Code 2 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 3
- Short/open Temperature Sensor wires between the Motor/Generator and the Inverter