Eaton Fuller Hybrid Fault Code 3 – Motor Generator Temperature

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 is measured through a thermistor sensor, which is located internal to the unit. The sensor changes 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 a 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 a high voltage (4.1 volts equals 32 °F [0 °C]).

Fault Code 3 Motor/Generator Temperature Detection

Inverter ignition voltage is greater than 7 volts and less than 16 volts (MY08)

Fault is detected when Inverter ignition voltage is greater than 7 volts and less than 16 volts (MY09)

Conditions to Set Fault Code Active

When the Motor/Generator temperature is warm the sensor resistance is low and the Inverter detects a 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 a high-voltage (4.1 volts equals 32 °F [0 °C ]). (MY08)

When the temperature sensor value is greater than 365 °F (185 °C) for 1 second. (MY09)

Fallback When Fault Code 3 is set the following conditions occur:
• Amber “Check Hybrid” light illuminates.
• Fault is stored in Hybrid Control Module (HCM) memory.
• Electric Motor/Generator Assist and Regeneration are disabled; however, the high-voltage relays remain powered.
• HCM continues to control the hybrid vehicle in a diesel-only mode.
• Transmission defaults start gear to 1st.

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 they have been Inactive for 200 hours.

This fault code can be caused by any of the following:

  • FMI 0 (FMI 0 is set when the temperature sensor value is greater than 365 °F [185 °C] for 1 second):
    • Inverter
    • Motor/Generator
    • Liquid cooling system (low coolant, no coolant flow, Coolant Pump, Radiator, Radiator Fan, reservoir)

Fault Code 3 – Motor/Generator Temperature Test

Component Identification MY08 Systems:

Delphi 56-Way Mating Connector View

Delphi 56-Way Mating Connector View

Temperature Sensor

Temperature Sensor
(Harness View – Front Side)

NOTE: Refer to the Eaton Hybrid Component and Connector Location for Connector Locations in MY08 Systems

component connector

Component Identification MY09 Systems:

Deutsch 40-Way Mating Connector View

Delphi 40-Way Mating Connector View

Terminal Side - Harness Connector Temperature Sensor

Terminal Side – Harness Connector Temperature Sensor

NOTE: Refer to the Eaton Hybrid Component and Connector Location for Connector Locations in MY09 Systems.

Eaton Fuller inverter motor/generator

STEP 1. Check for Active or Inactive fault code status.

  1. Review and follow the Warnings & Cautions.
  2.  Retrieve Active fault codes and FMIs with ServiceRanger using the 9-Way Diagnostic Connector.
    Warning: See High-Voltage Service Shutdown and Power-Up Procedures. Follow the procedures to avoid shock, burn or death from improperly handled high-voltage.
  3. Key on.
  4. Find initial temperature by selecting the “Data Monitor” option and view PID 113 “Motor/Generator Temperature” in the “Power Electronics” list.
  5. View PID 113 again after 20 minutes:
    • If PID 113 “Motor/Generator Temperature” dropped from the first reading, go to Step 2.
    • If PID 113 “Motor/Generator Temperature” remained the same, go to Step 8.

STEP 2. Verify level of hybrid system coolant.

  1. Key off.
  2. Observe the coolant level after the system has cooled down to ensure if is filled to the proper level:
    • If coolant is within the recommended limits, go to Step 3.
    • If coolant is below the recommended limits, refer to the OEM for coolant type and fill procedures. Check for source of coolant leak. When refilling the system it should be pressurized or vacuum bleed of air to ensure the coolant flows properly during normal operation.

STEP 3. Verify integrity of hybrid cooling system components.

  1. Key off
  2. Visually inspect the hybrid liquid cooling system radiator for debris, obstruction to airflow, or sharp bends in the coolant lines:
    • If the radiator is free of debris and the coolant lines are not bent sharply, go to Step 4.
    • If the radiator has debris, the airflow is obstructed, or the coolant lines are bent sharply, repair the concern, then go to Step 10.

STEP 4. Verify operation of hybrid Coolant Pump.

  1. Key on.
  2. Connect ServiceRanger to the 9-Way Connector in the cab.
  3. Select the Advanced Product Functions option and select the “Cooling Pump” option.
  4. Enable the “Cooling Pump” option:
    • If the Coolant Pump turns on, go to Step 5.
    • If the Coolant Pump does not turn on, go to Step 6.

STEP 5.Verify operation of hybrid Heat Exchanger Fan.

  1. Select the Advanced Product Functions option and select the “Heat Exchanger Fan” option.
  2. Enable the Heat Exchanger Fan option:
    • If the Heat Exchanger Fan turns on, the system needs to be purged of air, allowing the coolant to flow. Bleed the air by using a coolant system pressurizing tool or a vacuum tool, then go to Step 10.
    • If the Heat Exchanger Fan does not turn on, go to Step 8.

STEP 6. Verify voltage at hybrid Coolant Pump.

  1. Key on.
  2. Disconnect the Coolant Pump 2-Way Connector.
  3. Select the “Advanced Products Function” option and select “Cooling Pump.”
  4. Enable the “Cooling Pump” option:
  5.  Measure voltage at the 2-Way Connector from Pin A to Pin B:
    • If voltage between Pin A and Pin B is ±0.2 volts of battery voltage, refer to OEM for Coolant Pump concern.
    • If voltage between Pin A and Pin B is outside of range, refer to OEM for repair procedures on Cooling Pump Power Harness or damaged fuse.

STEP 7.Verify voltage at hybrid Heat Exchanger Fan.

  1. Key on.
  2. Disconnect the Heat Exchanger Fan 2- way connector.
  3. Select the “Advanced Products Function” option and select the “Heat Exchanger Fan.”
  4. Enable the Heat Exchanger Fan option:
  5. Measure voltage at the 2-Way Connector from Pin A to Pin B:
    • If voltage between Pin A and Pin B is ±0.2 volts of battery voltage, refer to OEM for Heat Exchanger Fan concern.
    • If voltage between Pin A and Pin B is outside of range, refer to OEM for repair procedures on Heat Exchanger Fan Power Harness or damaged fuse.

STEP 8. Verify continuity of Inverter circuitry.

  1. Key off.
  2. Disconnect the Inverter 56-Way Connector.
  3. Select the “Advanced Products Function” option and select “Cooling Pump.”
  4.  Measure resistance between Pin 38 and Pin 50(MY08) / 36 & 37 (MY09) and Pin 50 (MY08) / 37 (MY09) to ground of the Inverter 56-Way Connector.
    • If resistance is 0.8K–301.7K ohms between Pin 50 and Pin 38 and resistance between Pin 50 and ground is 10K ohms or greater, replace the Inverter, then go to Step 10.
    • If resistance is outside the range, go to Step 9.

STEP 9.Verify continuity of Temperature Sensor circuit.

  1. Key off.
  2. Disconnect the Motor/Generator Temperature Sensor 2-Way Connector located on the right side of the Motor/Generator.
  3. Measure resistance between the 2-Way Temperature Sensor Connector from Pin A to Pin B (MY08) / Pin 1 to Pin 2 (MY09) :
    • If resistance is 0.8K–301.7K ohms, repair the shorted HCM System Harness between the Inverter Connector and Motor/Generator 2-Way Connector.
    • If resistance is outside the range, replace the Motor/Generator, then go to Step 10.

STEP 10.Verify repair.

  1. Key off.
  2.  Reconnect all connectors and negative battery cable.
  3. Key on.
  4. Clear codes, see  Clear Inactive Faults.
  5. Drive the vehicle and attempt to reset the code.
  6. Check for codes, see View Active and Inactive Faults.
    • If no codes, test is complete.
    • If fault Code 3 appears, find error in testing, go to Step 1.
    • If a code other than 3 appears, see Fault Code Index List.

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