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
Warnings & Cautions

Danger: Danger indicates you will be severely injured or killed if do not follow the indicated procedure.
Warning: Warning indicates an immediate hazard, which could result in severe personal injury if you do not follow the indicated procedure.
Caution: Caution indicates vehicle or property damage could occur if you do not follow the indicated procedure.

Note: Note indicates additional detail that will aid in the diagnosis or repair of a component/system.

Follow the specified procedures in the indicated order to avoid personal injury:

1. If the high-voltage cones are around the vehicle and the lockout is installed on the PEC, the only person that should be allowed to start the vehicle is the person who signed the lockout tag.
2. Before working on a vehicle or leaving the cab while the engine is running, you should place the shift lever in “N” set the parking brake, and block the wheels.
3. For safety reasons, always engage the service brakes prior to selecting gear positions from “N.”
4. Before starting a vehicle always be seated in the driver’s seat, select “N” on the shift control, and set the parking brakes.
5. In vehicles with ePTO, the engine and/or
Motor/Generator can start in ePTO mode. Never perform any maintenance or work on vehicle, while in this mode.
6. 12-Volt Battery positive (+) and negative (-) must be disconnected prior to any welding on any Hybrid equipped vehicle.

Caution: Follow the specified procedures in the indicated order to avoid equipment malfunction or damage.
Caution: Do not release the parking brake or attempt to select a gear until the air pressure is at the correct level.
Caution: To avoid damage to the transmission during towing place the shift lever in “N” and lift the drive wheels off the ground or disconnect the driveline.

High-Voltage Warnings & Cautions

  • Use CO2 or Dry Chemical Fire Extinguishers.
  • The high-voltage wiring is covered in orange insulation or convoluted tubing and marked with warning labels at the connectors.
  • All Eaton® Hybrid Diesel/Electric vehicles will be marked ‘Hybrid’ on the outside of the vehicle, along with the shift label on the dash.
  • Refer to OEM for specific location of chassis mounted hybrid components.
  • Do NOT cut into the orange high-voltage cables.
  • Do NOT cut into or open the PEC.
  • Do NOT cut into or open the DC/DC Converter.
  • Do NOT cut into or open the Inverter.

A buffer zone must be set up and high-voltage insulated rubber gloves (class 0 with leather protectors) are required prior to working on high-voltage. Failure to follow these instructions may result in severe personal injury or death.
The rubber-insulated gloves that must be worn while working on the high-voltage system are class 0 with leather protectors. The rubber gloves should be tested before EVERY use following the rubber insulation gloves testing procedure found in “Diagnostic Tools/Service Publications” on page 6. Failure to follow these instructions may result in severe personal injury or death.
Before inspecting or working on any high-voltage cables or components the “High-Voltage Service Shutdown and Power-Up Procedure” on page 4 should be followed. Failure to follow these instructions may result in severe personal injury or death.
The Lockout and Tagout devices should only be removed by the technician that placed the Lockout and Tagout devices on the vehicle. Failure to follow these instructions may result in severe personal injury or death.
High-voltage rubber insulated gloves (class 0 with leather protectors) must be worn when working on any
high-voltage cables. The “High-Voltage Service Shutdown and Power-Up Procedure” on page 4 must be followed prior to removing any high-voltage cables. Failure to follow these instructions may result in severe personal injury or death.
High-voltage cables and wiring are orange and contain a warning label at the connectors. High-voltage components are marked with a label. High-voltage rubber insulated gloves (class 0 with leather protectors) must be used when working on any of these components. Failure to follow these instructions may result in severe personal injury or death.

High-Voltage Service Shutdown Procedures

High-Voltage Service Shutdown and Power-Up Procedure1. Follow “High-Voltage Work Area” procedure.
2. Locate the red PEC Service Switch on the front of the PEC and push switch off.
3. Remove the Service Switch Cover and install the Lockout Bracket (J48506).
4. Fasten tag to the Lockout Bracket.
5. Ensure the PEC Service Switch can not move from the off position.
6. Allow the system to set for a minimum of 5 minutes to discharge high voltage.
7. Connect ServiceRanger and view the Data Monitor PID 116 called “High-Voltage Battery Potential.” Use SPN 520323 for J1939 connection “Battery Voltage RB” (Relay Box).
8. The voltage should be 30 volts or less. If the voltage is above 30 volts, do not work on the vehicle and contact Eaton® at 1-800-826-HELP (4357).
9. Turn ignition key off and proceed to repair or troubleshooting step.
Note: The voltage drops to zero when the key is off.

High-Voltage Service Power-Up Procedure

1. Install all high-voltage connectors into their locked positions.
2. If you are the person working on the vehicle, remove the Lockout Bracket and tag.
3. Reinstall the Lockout Bracket over the Service Switch.
4. Pull the Service Switch out and let vehicle set for 2 minutes.
5. Start vehicle when appropriate.

Eaton Hybrid Component and Connector Location

Eaton Hybrid Component and Connector Locations MY08 Systems

Eaton Hybrid Component and Connector Location MY09 Systems

Eaton Hybrid Component and Connector Locations MY09 Systems

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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