Contents Wiring diagrams Section: Charging System All sections

Hybrid Engine Cooling System: Other Chevrolet Tahoe III

Charging System 10 illustrations ~2226 words

P0A01

The engine control module detects that the temperature difference between the generator control module temperature sensor parameter and the engine coolant temperature sensor is greater than 30°C (86°F).

P0A02

The engine control module detects that the generator control module temperature sensor parameter is less than -60.5°C (-76.9°F).

P0A03

The engine control module detects that the generator control module temperature sensor parameter is greater than 162°C (323.6°F).

Reference Information

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Control Module Cooling System Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(ref-364488-S04114729552010063000000)
  2. «Connector Repairs»(ref-364488-S23771656832010063000000)
  3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
  4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Engine running, observe the scan tool DMCM Coolant Temperature Signal parameter. The reading should be between -61 to +161°C (-77.8 to +321.8°F) depending on the current ambient temperature and the vehicle operating conditions.
  2. Operate the vehicle within the Conditions for Running the DTC.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Coolant Temperature Sensor Replacement (Generator Control Module)»(ref-364561-S30376739222010063000000)
  2. «Control Module References»(ref-364489-S22329914082010063000000) for engine control module replacement, setup, and programming

P0A7E

The hybrid powertrain control module detects an average battery temperature greater than 73°C (163.4°F) for 5 seconds.

P1ABE

One of the following conditions exists

  1. The drive motor generator battery control module detects an average battery temperature increase of 2°C (35.6°F) in a 20 second event for 3 consecutive events totaling 60 seconds.
  2. The drive motor generator battery control module detects 2 battery temperature sensors greater than 65°C (149°F) for 5 seconds.
  3. The drive motor generator battery control module detects any battery temperature sensor greater than 70°C (158°F).

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Battery Cooling Description

Electrical Information Reference

  1. «Circuit Testing»(ref-364488-S04114729552010063000000)
  2. «Connector Repairs»(ref-364488-S23771656832010063000000)
  3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
  4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit

  1. Verify that DTC P0A80, P0A81 or P0BBD is not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-364486-S07394808542010063000000) .
  2. Ignition ON, observe the scan tool BECM hybrid battery temperature parameters. The readings should be between -39 and +95°C (-38.2 and +203°F) with no greater than a 15°C ( 59°F) difference between any of the four temperature sensor readings. Refer to «Temperature Versus Resistance»(ref-364532-S38755933972010063000000) .

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Drive Motor Battery Sensor Module Wiring Harness Replacement»(ref-364532-S24594730892010063000000)
  2. «Control Module References»(ref-364489-S22329914082010063000000) for drive motor generator battery control module replacement, setup and programming

P0A81

Fan control signal monitor voltage to the drive motor generator battery control module is greater than 2.3 V or less than 0.5 V for 5 seconds.

P0BC1

The fan speed control circuit is greater than 0.9 V for 1 second.

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Battery Cooling Description

Electrical Information Reference

  1. «Circuit Testing»(ref-364488-S04114729552010063000000)
  2. «Connector Repairs»(ref-364488-S23771656832010063000000)
  3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
  4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit

Ignition ON, command the battery pack vent fan speed to 60 percent duty cycle with a scan tool. The battery pack vent fan should turn ON after approximately a 10 second delay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Drive Motor Battery Control Module Harness Replacement»(ref-364532-S39486127852010063000000)
  2. «Generator Battery Vent Fan Replacement»(ref-364561-S13869956282010063000000)
  3. «Generator Battery Vent Fan Relay Replacement»(ref-364561-S28968097952010063000000)
  4. «Control Module References»(ref-364489-S22329914082010063000000) for drive motor generator battery control module replacement, setup, and programming

P0A9C, P0AC6, P0ACB, and P0AE9

The hybrid battery temperature sensor is in normal operating range, but is 15°C (59°F) different from the other 3 sensors.

P0A9D, P0AC7, P0ACC, and P0AEA

The hybrid battery temperature is greater than 95°C (203°F) and one other temperature sensor is less than 70°C (158°F).

P0A9E, P0AC8, P0ACD, and P0AEB

The hybrid battery temperature is less than -40°C (-40°F).

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Battery Cooling Description

Electrical Information Reference

  1. «Circuit Testing»(ref-364488-S04114729552010063000000)
  2. «Connector Repairs»(ref-364488-S23771656832010063000000)
  3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
  4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit

  1. Verify that DTC P0A80, P0A81 or P0BBD is not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-364486-S07394808542010063000000)
  2. Ignition ON, observe the scan tool BECM hybrid battery temperature parameters. The readings should be between -39 and +95°C (-38.2 and +203°F) with no greater than a 15°C ( 59°F) difference between any of the four temperature sensor readings. Refer to «Temperature Versus Resistance»(ref-364532-S38755933972010063000000) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Drive Motor Battery Sensor Module Wiring Harness Replacement»(ref-364532-S24594730892010063000000)
  2. «Control Module References»(ref-364489-S22329914082010063000000) for drive motor generator battery control module replacement, setup and programming

P0AAF and P0AB4

The hybrid battery pack air temperature sensor 1 or 2 is less than -40°C (-40°F).

P0AAE and P0AB3

The hybrid battery pack air temperature sensor 1 or 2 is greater than 95°C (203°F).

P0AAD

The hybrid battery cooling fan is ON and the difference between sensor 1 and 2 is greater than 10°C (50°F) difference for 9 seconds.

P0AB2

The hybrid battery cooling fan is ON and the outlet air temperature is greater than maximum hybrid battery temperature value by 10°C (50°F) for 9 seconds.

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Battery Cooling Description

Electrical Information Reference

  1. «Circuit Testing»(ref-364488-S04114729552010063000000)
  2. «Connector Repairs»(ref-364488-S23771656832010063000000)
  3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
  4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit

  1. Verify that DTC P0A80, P0A81 or P0BBD is not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-364486-S07394808542010063000000) .
  2. Ignition ON, using a scan tool, command the hybrid battery pack fan speed to 60 percent and let it run for 2 minutes.
  3. Observe the scan tool hybrid battery air inlet and outlet temperature parameters. The readings should be between -39 and +95°C (-38.2 and +203°F) with no greater than a 10°C ( 50°F) difference. Refer to «Temperature Versus Resistance»(ref-364532-S38755933972010063000000) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Drive Motor Battery Sensor Module Wiring Harness Replacement»(ref-364532-S24594730892010063000000)
  2. «Control Module References»(ref-364489-S22329914082010063000000) for drive motor generator battery control module replacement, setup and programming

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Battery Cooling Description

Electrical Information Reference

  1. «Circuit Testing»(ref-364488-S04114729552010063000000)
  2. «Connector Repairs»(ref-364488-S23771656832010063000000)
  3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
  4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit

  1. Verify that DTC P0A80, P0A81, P0A9C, P0A9D, P0A9E, P0AC6, P0AC7, P0AC8, P0ACB, P0ACC, P0ACD, P0AE9, P0AEA, P0AEB, P0BC1, or P0BDD is not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-364486-S07394808542010063000000) .
  2. Ignition ON, observe the scan tool BECM hybrid battery temperature parameters. The readings should be between -39 and +95°C (-38.2 and +203°F) with no greater than a 15°C ( 59°F) difference between any of the four temperature sensor readings. Refer to «Temperature Versus Resistance»(ref-364532-S38755933972010063000000) .
  3. Using a scan tool, command the hybrid battery pack fan speed to 60 percent and let it run for 2 minutes.
  4. Observe the scan tool hybrid battery air inlet and outlet temperature parameters. The readings should be between -39 and +95°C (-38.2 and +203°F) with no greater than a 10°C ( 50°F) difference. Refer to «Temperature Versus Resistance»(ref-364532-S38755933972010063000000) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Drive Motor Battery Sensor Module Wiring Harness Replacement»(ref-364532-S24594730892010063000000)
  2. «Control Module References»(ref-364489-S22329914082010063000000) for drive motor generator battery control module replacement, setup and programming

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Delivery Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(ref-364488-S04114729552010063000000)
  2. «Connector Repairs»(ref-364488-S23771656832010063000000)
  3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
  4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, command the DMCM Coolant Pump ON and OFF with a scan tool.
  2. Observe the operation of DMCM coolant pumps.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(ref-364489-S22329914082010063000000) for ECM replacement, setup, and programming
  2. «Generator Control Module Coolant Pump Replacement (Left)»(ref-364561-S13865207002010063000000) or «Generator Control Module Coolant Pump Replacement (Right)»(ref-364561-S41716988042010063000000)

Hybrid Cooling System Loss of Coolant

StepActionYesNo
DEFINITION: The cooling system is loosing coolant either internally or externally.
1Inspect the coolant level. Is the coolant at the proper level?Go to Step 13Go to Step 2
2Fill the cooling system to the proper level. Refer to Generator Control Module Cooling System Draining and Filling . Is the action complete?Go to Step 3
3Overheating can cause a loss of coolant. Is the Hybrid Cooling system overheating?Go to Step 11Go to Step 4
4Visually inspect the hoses, pipes and hose clamps. Are any of the hoses, clamps or pipes leaking?Go to Step 12Go to Step 5
5Visually inspect the following components: Coolant surge tank Coolant pressure cap Drive motor generator control module Air separator Radiator Coolant pumps Are any of the listed components leaking?Go to Step 12Go to Step 6
6Pressure test the cooling system. Refer to Hybrid Cooling System Leak Test . With the cooling system pressurized, visually inspect the components listed in step 5. Are any leaks present?Go to Step 12Go to Step 7
7Pressure test the coolant pressure cap. Refer to Hybrid Cooling System Pressure Cap Testing . Does the coolant pressure cap hold pressure?Go to Step 9Go to Step 8
8Replace the coolant pressure cap. Is the repair complete?Go to Step 13
9Pressure test the cooling system. Refer to Hybrid Cooling System Leak Test . With the cooling system pressurized, remove the engine cooling system pressure cap. Does the hybrid cooling system hold pressure?Go to Step 10
10Replace the surge tank. Refer to Radiator Surge Tank Replacement (Non-HP2) or Radiator Surge Tank Replacement (HP2) . Is the repair complete?Go to Step 13
11Repair the hybrid cooling system overheating condition. Refer to Hybrid Cooling System Overheating (Electrical) . Is the repair complete?Go to Step 13
12Repair or replace the leaking component. Refer to the appropriate repair. Is the repair complete?Go to Step 13
13Operate the system in order to verify the repair. Did you find and correct the condition?System OKGo to Step 2

Filling Procedure

  1. Install the generator control module coolant pump hose. Refer to «Generator Control Module Coolant Pump Hose Replacement (Pump to Pump)»(ref-364561-S21604743372010063000000) or «Generator Control Module Coolant Pump Hose Replacement (Pump to Radiator)»(ref-364561-S04309229522010063000000) .
  2. Using the J 38185 , reposition the generator control module coolant pump hose clamp.
  3. Install the generator control module coolant inlet hose. Refer to «Generator Control Module Coolant Inlet Hose Replacement»(ref-364561-S40177867672010063000000) .
  4. Using the J 38185 , reposition the generator control module coolant inlet hose clamp.
  5. Lower the vehicle.
  6. Slowly fill the cooling system with the pre-mixed DEXCOOL. Refer to «Approximate Fluid Capacities»(ref-364508-S03245074232010063000000) .
  7. Turn the ignition ON.
  8. As the cooling pumps run, air will purge into the surge tank and the coolant level will drop. Top off the coolant as necessary until the coolant is maintained at the Cold Full line.
  9. Inspect the concentration of the generator control module coolant using the J 26568 .
  10. Install the coolant pressure cap.

Scheme 49

Scheme 49: Generator Control Module Coolant Pump Hose Replacement (Pump to Pump)
CalloutComponent Name
Preliminary Procedures Drain the cooling system. Refer to Generator Control Module Cooling System Draining and Filling . Raise the vehicle. Refer to Lifting and Jacking the Vehicle . Remove the engine shield. Refer to Engine Shield Replacement .
1Generator Control Module Coolant Pump Hose Procedure: Using J 38185 reposition the generator control module coolant pump hose clamps. Special Tools: J 38185 Hose Clamp Pliers

Scheme 50

Scheme 50: Generator Control Module Coolant Pump Hose Replacement (Pump to Radiator)
CalloutComponent Name
Preliminary Procedures Drain the cooling system. Refer to Generator Control Module Cooling System Draining and Filling . Raise the vehicle. Refer to Lifting and Jacking the Vehicle . Remove the engine shield. Refer to Engine Shield Replacement .
1Generator Control Module Coolant Pump Hose Procedure: Using J 38185 reposition the generator control module coolant pump hose clamps. Special Tools: J 38185 Hose Clamp Pliers

Scheme 51

Scheme 51: Generator Control Module Coolant Inlet Hose Replacement
CalloutComponent Name
Preliminary Procedures Drain the cooling system. Refer to Generator Control Module Cooling System Draining and Filling . Raise the vehicle. Refer to Lifting and Jacking the Vehicle . Remove the engine shield. Refer to Engine Shield Replacement . Remove the air cleaner. Refer to Air Cleaner Assembly Replacement . Remove the air cleaner resonator outlet duct. Refer to Air Cleaner Resonator Outlet Duct Replacement .
1Generator Control Module Coolant Inlet Hose Procedure: Using J 38185 reposition the generator control module coolant hose clamps. Special Tools: J 38185 Hose Clamp Pliers

Scheme 52

Scheme 52: Generator Control Module Coolant Outlet Hose Replacement
CalloutComponent Name
Preliminary Procedures Drain the cooling system. Refer to Generator Control Module Cooling System Draining and Filling . Remove the air cleaner. Refer to Air Cleaner Assembly Replacement . Remove the air cleaner resonator outlet duct. Refer to Air Cleaner Resonator Outlet Duct Replacement .
1Generator Control Module Coolant Outlet Hose Procedure: Using J 38185 reposition the generator control module coolant hose clamps. Special Tools: J 38185 Hose Clamp Pliers

Scheme 53

Scheme 53: Generator Control Module Coolant Pump Replacement (Left)
CalloutComponent Name
Preliminary Procedures Drain the cooling system. Refer to Generator Control Module Cooling System Draining and Filling . Raise the vehicle. Refer to Lifting and Jacking the Vehicle . Remove the engine shield. Refer to Engine Shield Replacement . Remove the generator control module coolant pump hose (pump to pump) Refer to Generator Control Module Coolant Pump Hose Replacement (Pump to Pump) or Generator Control Module Coolant Pump Hose Replacement (Pump to Radiator) . Remove the generator control module coolant pump hose (pump to radiator) Refer to Generator Control Module Coolant Pump Hose Replacement (Pump to Pump) or Generator Control Module Coolant Pump Hose Replacement (Pump to Radiator) .
1Generator Control Module Coolant Pump Bolt (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 9 N.m (80 lb in)
2Generator Control Module Coolant Pump Tip: Disconnect electrical connector.
CAUTION
Refer to Fastener Caution .

Scheme 54

Scheme 54: Generator Control Module Coolant Pump Replacement (Right)
CalloutComponent Name
Preliminary Procedures Drain the cooling system. Refer to Generator Control Module Cooling System Draining and Filling . Raise the vehicle. Refer to Lifting and Jacking the Vehicle . Remove the engine shield. Refer to Engine Shield Replacement . Remove the generator control module coolant pump hose (pump to pump) Refer to Generator Control Module Coolant Pump Hose Replacement (Pump to Pump) or Generator Control Module Coolant Pump Hose Replacement (Pump to Radiator) . Remove the radiator surge tank outlet hose. Refer to Generator Control Module Coolant Inlet Hose Replacement .
1Generator Control Module Coolant Pump Bolt (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 9 N.m (80 lb in)
2Generator Control Module Coolant Pump Tip: Disconnect electrical connector.
CAUTION
Refer to Fastener Caution .

Scheme 55

Scheme 55: Generator Control Module Coolant Radiator Replacement
CalloutComponent Name
Preliminary Procedures Drain the cooling system. Refer to Generator Control Module Cooling System Draining and Filling . Remove radiator air upper baffle and deflector. Refer to Radiator Air Upper Baffle and Deflector Replacement (Yukon) or Radiator Air Upper Baffle and Deflector Replacement (Cadillac) . Remove the condenser. Refer to Air Conditioning Condenser Replacement (Gas) . Remove transmission cooler pipes. Refer to Transmission Fluid Cooler Pipe Replacement . Remove the generator control module coolant outlet hose. Refer to Generator Control Module Coolant Outlet Hose Replacement . Remove the generator control coolant pump hose (pump to radiator). Refer to Generator Control Module Coolant Pump Hose Replacement (Pump to Pump) or Generator Control Module Coolant Pump Hose Replacement (Pump to Radiator) .
1Radiator Tab (Qty: 2) Procedure: Push tabs in and lift up on generator control module coolant radiator.
2Generator Control Module Coolant Radiator.

Scheme 56

Scheme 56: Generator Battery Vent Fan Relay Replacement
CalloutComponent Name
WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. Preliminary Procedures: Disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling . Remove the upper cover and the front cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement .
1Generator Battery Vent Fan Relay Procedure:: After relay has been replaced, enable the HV system. Refer to High Voltage Enabling .
WARNING
Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death.

Scheme 57

Scheme 57: Generator Battery Vent Fan Replacement
CalloutComponent Name
WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. Preliminary Procedures Disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling . Remove the upper cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement . Remove the outlet ducts. Refer to Drive Motor Battery Cooling Air Outlet Duct and Front Air Outlet Duct Replacement .
1Drive Motor Battery Cable Terminal Nut CAUTION: Refer to Fastener Caution . Tip: Remove cable retainer from battery fan assembly. When cable is removed, install protective cover to cable end. Tighten: 5 N.m (44 lb in)
2Generator Battery Vent Fan Bolt Tighten: 6 N.m (53 lb in)
3Drive Motor Generator Battery Cooling Blower Nut (Qty: 2) Tighten: 6 N.m (53 lb in)
4Generator Battery Vent Fan Procedure: Disconnect the wiring connections. Lift off from the inlet duct housing. After vent van has been replaced, enable the HV system. Refer to High Voltage Enabling .
WARNING
Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death.
CAUTION
Refer to Fastener Caution .

Scheme 58

Scheme 58: Drive Motor Battery Cooling Air Outlet Duct and Front Air Outlet Duct Replacement
CalloutComponent Name
WARNING: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. Preliminary Procedures: Disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling . Remove the upper cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement .
1Battery Cooling Front Air Outlet Duct Tip: Tilt the duct from left side to ease removal.
2Drive Motor Generator Battery Cooling Outlet Duct Retainer
3Drive Motor Generator Battery Cooling Air Outlet Duct Procedure:: After outlet duct has been replaced, enable the HV system. Refer to High Voltage Enabling .
WARNING
Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death.

Air Cooling

The drive motor generator battery is cooled by a vent fan motor. The vent fan motor and vent fan motor relay are located inside the drive motor battery assembly. B+ to the vent fan is provided from vent fan relay when the battery energy control module (BECM) supplies a ground to the relay. The battery vent fan draws the air through the batteries to cool them. There are several foam seals internal to the drive motor generator battery in order to prevent air leaks. The exhaust air exits from hybrid drive motor generator battery in the rear and is routed through a duct into the floor panel of the vehicle. The hybrid battery air inlet temperature sensor is located on the inlet air duct for the hybrid battery fan, and the battery air outlet temperature sensor is located in the air passage above the hybrid batteries. These sensors are used by the battery energy control module (BECM) to determine air flow. Refer to Drive Motor Generator Control Module Description and Operation .

Electrolyte Venting

Each of the 40 hybrid batteries has a vent for electrolyte gas that is located on the top of each battery. The hybrid batteries vent system connects all of the 40 hybrid battery vents to a rubber manifold. The vent exits the hybrid drive motor generator battery through a single hose in the rear and is vented through the floor panel of the vehicle. These vents are mechanical and will only open when a predetermined amount of internal battery pressure is reached.

Hybrid Cooling

The drive motor generator power inverter module (PIM) assembly converts high voltage direct current (DC) electrical energy to 3 phase alternating current (AC) electrical energy. The accessory DC power converter module (APM) converts high voltage DC electric energy into low voltage (14 V) and intermediate voltage (42 V) in order to charge the vehicles accessory battery and supply electric energy to the 42 V power steering system. The APM and PIM are fastened together and are referred to as the drive motor/generator control module assembly. The engine control module (ECM) monitors a temperature sensor in the power electronics cooling system and operates the radiator fan and the power electronics coolant pump in response to power electronics cooling system temperature.

The drive motor/generator control module assembly is cooled with pre-mixed Dexcool® circulating through a cooling system that is separate from the engine cooling system.The coolant uses 50/50 mix of Dex-cool and de-ionized water. De-ionized water is required in order to prevent corrosion from effecting heatsink performance. Always use pre-mixed coolant and never use tap water in the power electronics coolant system. The pump system will always be activated when the vehicle is on and propulsion is available. The pump system will also be activated when the vehicle is on and propulsion is not available if the algorithms determine that cooling is needed. The HCP and ECM determine the speed/flow and control the power electronics coolant pump system. This circuit is a single driver control to a relay and both pumps are in parallel powered by a fuse in the auxiliary BEC. The power electronics coolant pump control shall be on during a key crank, after a successful key crank, during a jump assist event or after a key off when the power electronics coolant is extremely hot.