Hybrid Engine Cooling System Cadillac Escalade GMT900

Fastener Tightening Specifications

Scheme 44

Scheme 45

Generator Battery Temperature Sensor Location

Hybrid Battery Temperature Sensor Location

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit/System Description

The generator control module temperature sensor is a variable resistor that measures the temperature of the coolant entering the generator control module coolant radiator. The engine control module (ECM) supplies 5 V to the generator control module temperature signal circuit, and a ground for the generator control module temperature low reference circuit.

Conditions for Running the DTC

P0A01

1. DTCs P0112, P0113, P0117, P0118, P0101, P0102, P0103, P0A02, P0A03 and P2610 are not set.
2. The ignition has been OFF for greater than 8 hours.
3. The temperature difference between the intake air temperature and engine coolant temperature sensors is less than or equal to 16°C (60.8°F) at ignition ON.

P0A02

1. DTCs P0112 or P0113 are not set.
2. The engine is running for greater than 10 seconds.
3. The intake air temperature is greater than 70°C (158°F).
4. This DTC runs continuously when the above conditions are met.

P0A03

1. DTCs P0112 or P0113 are not set.
2. The engine is running for greater than 10 seconds.
3. The intake air temperature is greater than -20°C (-4°F).
4. This DTC runs continuously when the above conditions are met.

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).

Action Taken When the DTC Sets

DTCs P0A01, P0A02 and P0A03 are Type B DTCs.

1. The cooling fans will be commanded to high speed.
2. The DIC will display A/C Inoperative

Conditions for Clearing the MIL/DTC

1. DTCs P0A01, P0A02 and P0A03 are Type B DTCs.
2. P0A01 requires that the engine control module detect that the temperature difference between the generator control module temperature sensor parameter and the engine coolant temperature sensor is less than or equal to 16°C (60.8°F) at ignition ON.

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»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

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.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the generator control module temperature sensor.
2. Ignition OFF for 90 seconds, test for less than 5 ohms between the low reference circuit terminal A and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the engine control module.
3. Ignition ON, verify the scan tool DMCM Coolant Temperature parameter is greater than 162°C (323.6°F). If less than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the engine control module.
4. Install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool DMCM Coolant Temperature parameter is less than -60.5°C (-76.9°F). If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the engine control module.
5. If all circuits test normal, test or replace the generator control module temperature sensor.

Component Testing

Temperature Sensor Test

1. Test the generator control module coolant temperature sensor by varying the sensor temperature while monitoring the sensor resistance.
2. Compare the readings with the «Temperature Versus Resistance»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) . If not within the specified range, replace the generator control module coolant temperature sensor.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Coolant Temperature Sensor Replacement (Generator Control Module)»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system)
2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Typical Scan Tool Data

Hybrid Batt. Mod. 1-4 Temperature

The drive motor generator battery has four hybrid battery temperature sensors. The hybrid battery temperature sensors are located on the top of the hybrid batteries. The temperature sensor is a variable resistor that measures the temperature of the hybrid batteries. The drive motor generator battery control module (BECM) supplies 5 V to the signal circuit and a ground for the low reference circuit. The hybrid battery temperature sensor resistance changes with battery temperature. The lower the temperature, the higher the resistance of the sensor. The higher the temperature, the lower the resistance of the sensor. The drive motor generator battery control module uses the battery temperature sensors to control the battery cooling fan operation.

The hybrid powertrain control module monitors the average battery pack temperature over serial data. When the average drive motor generator battery temperature exceeds the calibrated temperature the hybrid powertrain control module will set DTC P0A7E and send a command to the drive motor generator battery control module to open the high voltage contactors.

1. DTC P0A9C, P0A9D, P0A9E, P0AC6, P0AC7, P0AC8, P0ACB, P0ACC, P0ACD, P0AE9, P0AEA, or P0AEB is not set.
2. The ignition is ON.
3. The 12 V battery voltage is 9-18 V.

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).

P0A7E

1. DTC P0A7E is a type C DTC.
2. The hybrid powertrain control module commands the drive motor generator battery control module to open the high voltage contactors relays when the vehicle speed is below 5 km/h (3 mph).

P1ABE

1. DTC P1ABE is a type C DTC.
2. The drive motor generator battery control module sends a message to the hybrid powertrain control module requesting the high voltage contactors open. The hybrid powertrain control module will command the contactors relays open when the vehicle speed is less than 5 km/h (3 mph).

Conditions for Clearing the DTC

DTCs P0A7E and P1ABE are type C DTCs.

Diagnostic Aids

1. Battery temperatures can be affected by vehicle load, outside temperature and customer driving conditions. Test drive the vehicle, and attempt to simulate the Freeze Frame/Failure Record conditions this DTC set under.
2. Inspect for the following: Air inlet and outlet for blockage. Loose or poor connections at the drive motor generator battery control module temperature sensor module X3 harness connector. Damage to the drive motor generator battery control module temperature sensor module wiring harness. Damage to the fan or blades. Damage to the internal drive motor generator battery cooling air outlet duct seals.
3. Test the resistance across each temperature sensor 5 V reference and low reference circuits. Refer to «Temperature Versus Resistance»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) .
4. If the hybrid batteries are at or above the temperature values for setting these DTCs, allow the hybrid batteries to cool down by letting the vehicle stand at room temperature, this could take 4 to 8 hours.
5. Use the scan tool output control to test the drive motor generator battery vent fan operation.
6. Inspect the ground circuit for the drive motor generator battery vent fan relay.
7. Inspect the drive motor generator battery vent fan relay connections.
8. Refer to «Generator Battery Temperature Sensor Location»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system__generator-battery-temperature-sensor-location) for the proper locations of the four temperature sensors.

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»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
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»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) .

1. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) .
2. Verify that none of the following conditions exist: The inlet and outlet air vents do not have any obstructions or blockages. The vent fan blades are not broken or damaged. The internal foam seals are not missing or damaged. If any conditions are found, remove, repair or replace as necessary.
3. Ignition OFF, disconnect the X3 harness connector at the drive motor generator battery control module.
4. Test for 1k ohms-209k ohms between the terminals listed below. The resistance of each temperature sensor should be within the specified range, and within 500 ohms of each other. Refer to «Temperature Versus Resistance»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) . Sensor 1-5 V reference circuit terminal 1 and low reference circuit terminal 2 Sensor 2-5 V Reference circuit terminal 3 and low reference circuit terminal 4 Sensor 3-5 V Reference circuit terminal 5 and low reference circuit terminal 6 Sensor 4-5 V Reference circuit terminal 7 and low reference circuit terminal 8 If not within the specified range, replace the drive motor battery sensor module wiring harness.
5. If all circuits test normal, replace the drive motor generator battery control module.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Drive Motor Battery Sensor Module Wiring Harness Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system)
2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for drive motor generator battery control module replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator battery is cooled by a drive motor battery vent fan motor. The battery vent fan motor and battery vent fan relay are located inside the drive motor generator battery assembly. B+ to the battery vent fan is provided from the battery vent fan relay when the drive motor generator battery control module (BECM) supplies a ground to the battery vent fan relay. A ground wire from the battery vent fan motor assembly completes the path to case ground. A 5 V circuit is provided from the battery vent fan motor assembly, to the drive motor generator battery control module. The drive motor generator battery control module uses a pulse width modulated (PWM) signal on the 5 V circuit to control the battery vent fan motor duty cycle. The drive motor generator battery control module uses 4 battery temperature sensors, one air inlet duct and one air outlet temperature sensor to control battery vent fan motor operation and speed.

P0A81

1. The ignition is ON.
2. Battery voltage is 9-18 V.
3. The fan speed is commanded 35 percent or greater.

P0BC1

1. The ignition is ON.
2. Battery voltage is 9-18 V.
3. The fan has transitioned from either ON to OFF or from OFF to ON.

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.

DTCs P0A81 and P0BC1 are type B DTCs.

DTCs P0A81 and P0BC1 are type B DTCs.

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»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

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.

Note. Perform the Generator Battery Vent Fan test first

Generator Battery Vent Fan Test

1. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) .
2. Ignition OFF, disconnect the generator battery vent fan.
3. Connect the 12 V battery.
4. Test for less than 5 ohms between the generator battery vent fan ground circuit terminal 3 and ground If greater than the specified range, test the ground circuit for an open/high resistance.
5. Connect a test lamp between the control circuit terminal 2 and the ground circuit terminal 3.
6. Command the battery pack vent fan speed between 0 and 60 percent with a scan tool. The test lamp should turn ON and OFF after a 10 second delay. If the test lamp does not turn ON and OFF, refer to Generator Battery Vent Fan Relay test.
7. Connect a DMM between the control circuit terminal 4 and ground.
8. Command the battery vent fan to 60 percent with a scan tool. Test for less than 1 V after a 10 second delay. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the drive motor generator battery control module.
9. Command the battery vent fan to 0 percent with a scan tool. Switch the DMM to the diode test. The DMM reading should display O.L. If less than the specified value, test the control circuit for a short to ground. If the circuits test normal, replace the drive motor generator battery control module.
10. Command the battery vent fan to 60 percent with a scan tool. The reading should be less than 3 V. If less than the specified range or displaying O.L., test the control circuit for an open/high resistance. If the circuits test normal, replace the drive motor generator battery control module.

Generator Battery Vent Fan Relay Test

1. Disconnect the harness connector at the battery vent fan relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 4 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 4 for a short to ground. If the circuit tests normal, replace the battery vent fan relay.
4. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Connect a 15 A fused jumper wire between the B+ circuit terminal 3 and the control circuit terminal 4. Verify the generator battery vent fan is activated. If the cooling fan does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the generator battery vent fan.
6. Connect a test lamp between the B+ circuit terminal 2 and the control circuit terminal 1.
7. Command the battery pack vent fan speed between 0 and 60 percent with a scan tool. The test lamp should turn ON and OFF after a 10 second delay. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the drive motor generator battery control module. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the drive motor generator battery control module.
8. If all circuits test normal, test or replace the generator battery vent fan relay.

Fan Relay Test

1. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) .
2. Ignition OFF, disconnect the drive motor generator battery vent fan relay.
3. Test for 85-110 ohms between terminals 1 and 2. If not within the specified range, replace the relay.
4. Test for infinite resistance between the following terminals: 1 and 3 1 and 4 2 and 3 2 and 4 3 and 4 If not the specified value, replace the relay.
5. Install a 5 A fused jumper wire between relay terminal 2 and 12 V. Install a jumper wire between relay terminal 1 and ground. Test for less than 2 ohms between terminals 3 and 4. If greater than the specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor Battery Control Module Harness Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system)
2. «Generator Battery Vent Fan Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system)
3. «Generator Battery Vent Fan Relay Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system)
4. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for drive motor generator battery control module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Hybrid Batt. Mod. 1-4 Temperature

The drive motor generator battery has four hybrid battery temperature sensors. The hybrid battery temperature sensors are located on the top of the hybrid batteries. The temperature sensor is a variable resistor that measures the temperature of the hybrid batteries. The control module supplies 5 V to the signal circuit and a ground for the low reference circuit. The hybrid battery temperature sensor resistance changes with battery temperature. The lower the temperature, the higher the resistance of the sensor. The higher the temperature, the lower the resistance of the sensor. The drive motor generator battery control module (BECM) uses the battery temperature sensors to determine the hybrid battery temperature to control the battery cooling fan operation.

1. The ignition is ON.
2. The 12 V battery voltage is 9-18 V.

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).

1. DTCs P0A9C, P0A9D, P0A9E, P0AC6, P0AC7, P0AC8, P0ACB, P0ACC, P0ACD, P0AE9, P0AEB, and P0AEA are type B DTCs.
2. If two sensors fail, the drive motor generator battery sends a message to the hybrid powertrain control module to reduce the power use limit to 50 percent and the battery vent fan will default to run.
3. If all four sensors fail, the state of charge (SOC) will be considered invalid.

DTCs P0A9C, P0A9D, P0A9E, P0AC6, P0AC7, P0AC8, P0ACB, P0ACC, P0ACD, P0AE9, P0AEB, and P0AEA are type B DTCs.

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»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list)
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»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) .

1. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) .
2. Verify that none of the following conditions exist: the inlet and outlet air vents do not have any obstructions or blockages the vent fan blades are not broken or damaged the internal foam seals are not missing or damaged If any conditions are found, remove, repair or replace as necessary.
3. Ignition OFF, disconnect the X3 harness connector at the drive motor generator battery control module.
4. Test for 1k ohms-209k ohms between each of the terminals listed below. The resistance of each temperature sensor should be within the specified range, and within 500 ohms of each other. Refer to «Temperature Versus Resistance»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) . Sensor 1-5 V reference circuit terminal 1 and low reference circuit terminal 2 Sensor 2-5 V Reference circuit terminal 3 and low reference circuit terminal 4 Sensor 3-5 V Reference circuit terminal 5 and low reference circuit terminal 6 Sensor 4-5 V Reference circuit terminal 7 and low reference circuit terminal 8 If not within the specified range, replace the drive motor battery sensor module wiring harness.
5. If all circuits test normal, replace the drive motor generator battery control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor Battery Sensor Module Wiring Harness Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system)
2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for drive motor generator battery control module replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Hybrid Batt. Inlet Air Temperature

Hybrid Batt. Outlet Air Temperature

The drive motor generator battery assembly has an air inlet and air outlet temperature sensors. The air inlet and air outlet temperature sensors are located on the inlet and outlet air ducts of the hybrid battery vent fan. The air inlet temperature sensor is referred to as sensor 1 and the air outlet temperature sensor is referred to as sensor 2. The air temperature sensors are a variable resistor that measures the temperature of the inlet and outlet air. The control module supplies 5 V to the signal circuit and a ground for the low reference circuit. The air inlet and outlet temperature sensor resistance changes with temperature. The lower the temperature, the higher the resistance of the sensor. The higher the temperature, the lower the resistance of the sensor. The drive motor generator battery control module (BECM) uses the air inlet and outlet temperature sensors to determine if air is circulating through the drive motor generator battery assembly.

1. The ignition is ON.
2. The 12 V battery voltage is 9-18 V.

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.

1. DTCs P0AAD, P0AAE, P0AAF, P0AB2, P0AB3, and P0AB4 are type B DTCs.
2. The drive motor generator battery sends a message to the hybrid powertrain control module to reduce the power by 50 percent.

DTCs P0AAD, P0AAE, P0AAF, P0AB2, P0AB3, and P0AB4 are type B DTCs.

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»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
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»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) .

1. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) .
2. Verify that none of the following conditions exist: the inlet and outlet air vents do not have any obstructions or blockages the vent fan blades are not broken or damaged the internal foam seals are not missing or damaged If any conditions are found, remove, repair or replace as necessary.
3. Ignition OFF, disconnect the X3 harness connector at the drive motor generator battery control module.
4. Test for 1k ohms-209k ohms between each of the terminals listed below. The resistance of each temperature sensor should be within the specified range, and within 500 ohms of each other. Refer to «Temperature Versus Resistance»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) . Sensor 1-5 V reference circuit terminal 9 and low reference circuit terminal 10 Sensor 2-5 V reference circuit terminal 11 and low reference circuit terminal 12 If not within the specified range, replace the drive motor battery sensor module wiring harness.
5. If all circuits test normal, replace the drive motor generator battery control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor Battery Sensor Module Wiring Harness Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system)
2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for drive motor generator battery control module replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator battery has four hybrid battery temperature sensors, an air inlet temperature sensor and an air outlet temperature sensor. The air inlet temperature sensor is referred to as sensor 1 and the air outlet temperature sensor is referred to as sensor 2. The hybrid battery temperature sensors are located on the top of the hybrid batteries. Both the hybrid battery temperature sensors and the air inlet and outlet sensors are a variable resistor that measures the temperature. The control module supplies 5 V to the signal circuit and a ground for the low reference circuit. The temperature sensor resistance changes with temperature. The lower the temperature, the higher the sensor resistance. The higher the temperature, the lower the sensor resistance. The drive motor generator battery control module (BECM) uses these temperature sensors to determine the hybrid battery temperature and to control the battery vent fan operation.

1. The ignition is ON.
2. The 12 V battery voltage is 9-18 V.
3. The drive motor generator battery vent fan is ON.

Conditions for Setting the DTC

1. DTCs P0AAE and P0AAF are not set.
2. Drive motor generator battery air inlet temperature is less than 38°C ( 100.4°F) and the drive motor generator battery control module detects the max battery temperature is more than 58°C (136.4°F) for 120 seconds.

DTC P0C32 is a type B DTC.

DTC P0C32 is a type B DTC.

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»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

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»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
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»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) .
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»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) .

1. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to «High Voltage Disabling»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__high-voltage-disabling) .
2. Verify that none of the following conditions exist: the inlet and outlet air vents do not have any obstructions or blockages the vent fan blades are not broken or damaged the internal foam seals are not missing or damaged If any conditions are found, remove, repair or replace as necessary.
3. Ignition OFF, disconnect the X3 connector at the drive motor generator battery control module.
4. Test for 1k ohms-209k ohms between the terminals listed below. The resistance of each temperature sensor should be within the specified range, and within 500 ohms of each other. Refer to «Temperature Versus Resistance»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system__temperature-versus-resistance) . Air Temperature Sensor 1-5 V reference circuit terminal 9 and low reference circuit terminal 10 Air Temperature Sensor 2-5 V reference circuit terminal 11 and low reference circuit terminal 12 Battery Temperature Sensor 1-5 V reference circuit terminal 1 and low reference circuit terminal 2 Battery Temperature Sensor 2-5 V reference circuit terminal 3 and low reference circuit terminal 4 Battery Temperature Sensor 3-5 V reference circuit terminal 5 and low reference circuit terminal 6 Battery Temperature Sensor 4-5 V reference circuit terminal 7 and low reference circuit terminal 8 If not within the specified range, replace the drive motor battery sensor module wiring harness.
5. If all circuits test normal, replace the drive motor generator battery control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor Battery Sensor Module Wiring Harness Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-energy-storage-system)
2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for drive motor generator battery control module replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The APM and PIM are fastened together and are referred to as the drive motor/generator control module assembly. The drive motor/generator control module assembly is cooled with pre-mixed DEX-COOL® circulating through a cooling system that is separate from the engine cooling system. The power electronics cooling system utilizes a heat exchanger at the front of the vehicle and two electric pumps to circulate the coolant. 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.

Be sure DTC's P0C11, P0C12, P0C13, P0C14, P0C15 or P0C16 are not set. If any of these codes are set diagnose these first.

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»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

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.

1. Disconnect the coolant pump relay.
2. Ignition ON, verify that a test lamp does not illuminate between the relay controlled output circuit terminal 87 and ground. If the test lamp illuminates, test the relay controlled output circuit for a short to voltage.
3. Verify that a test lamp illuminates between the relay coil B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the relay coil B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay coil B+ circuit fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the coolant pump relay.
4. Verify that a test lamp illuminates between the relay switch B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the relay switch B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the appropriate DMCM coolant pump.
6. Test for less than 5.0 ohms between the coolant pump ground circuit terminal 1 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the coolant pump.
8. Connect a 15 A fused jumper wire between the relay switch B+ circuit terminal 30 and the relay controlled output circuit terminal 87. Verify the coolant pump is activated. If the coolant pump does not activate, test the relay controlled output circuit for an open/high resistance. If the circuit tests normal, test or replace the coolant pump.
9. Connect a test lamp between the relay coil B+ circuit terminal 85 and the relay coil control circuit terminal 86.
10. Command the DMCM coolant pump ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the ECM. If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
11. If all circuits test normal, test or replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
2. «Generator Control Module Coolant Pump Replacement (Left)»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system) or «Generator Control Module Coolant Pump Replacement (Right)»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system)

Hybrid Cooling System Loss of Coolant

Hybrid Cooling System Pressure Cap Testing

Special Tools

1. J 24460-01 Cooling System Pressure Tester
2. J 46143 Cooling System Adapter. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system__special-tools) .

Pressure Cap Testing

1. Remove the pressure cap.
2. Wash the pressure cap sealing surface with water.
3. Use the J 24460-01 (1) with J 46143 (2) in order to test the pressure cap. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system__special-tools) .
4. Test the pressure cap for the following conditions: Pressure release when the J 24460-01 exceeds the pressure rating of the pressure cap. Maintain the rated pressure for at least 10 seconds. Note the rate of pressure loss.
5. Replace the pressure cap under the following conditions: The pressure cap does not release pressure which exceeds the rated pressure of the cap. The pressure cap does not hold the rated pressure.

Hybrid Cooling System Leak Test

Special Tools

1. J 24460-01 Cooling System Pressure Tester
2. J 46143 Cooling System Adapter. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system__special-tools) .

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Hybrid Cooling System Pressure Cap Testing»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system__hybrid-cooling-system-pressure-cap-testing) .
3. Wash the pressure cap mating surface with water.
4. Use the J 24460-01 with the J 46143 in order to apply pressure to the cooling system. See «Special Tools»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system__special-tools) . Do not exceed the pressure cap rating.
5. The cooling system should hold the rated pressure for at least 2 minutes. Observe the gauge for any pressure loss.
6. Repair any leaks as required.

Scheme 46

Generator Control Module Cooling System Draining and Filling

Special Tools

1. J 26568 Coolant and Battery Tester
2. J 38185 Hose Clamp Pliers

Draining Procedure

1. Follow the steps below in order to remove the surge tank fill cap: Slowly rotate the cap counterclockwise. Stop rotating and allow the hissing to stop. After all the hissing stops, continue turning counterclockwise in order to remove the cap.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#general-information__lifting-and-jacking-the-vehicle) .
3. Place a drain pan under the generator control module coolant pump hose. Refer to «Generator Control Module Coolant Pump Hose Replacement (Pump to Pump)»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system) or «Generator Control Module Coolant Pump Hose Replacement (Pump to Radiator)»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system) .
4. Using the J 38185 , reposition the generator control module coolant pump hose clamp.
5. Remove the generator control module coolant pump hose from the coolant pump.
6. Drain the coolant.
7. Place a drain pan under the generator control module coolant inlet hose. Refer to «Generator Control Module Coolant Inlet Hose Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system) .
8. Using the J 38185 , reposition the generator control module coolant inlet hose clamp.
9. Drain the coolant.

Filling Procedure

1. Install the generator control module coolant pump hose. Refer to «Generator Control Module Coolant Pump Hose Replacement (Pump to Pump)»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system) or «Generator Control Module Coolant Pump Hose Replacement (Pump to Radiator)»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system) .
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»(/cadillac/escalade/gmt900-2006-2014/remont/charging-system/#hybrid-engine-cooling-system) .
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»(/cadillac/escalade/gmt900-2006-2014/remont/lubrication-system/#maintenance-and-lubrication__approximate-fluid-capacities) .
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 47

Scheme 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

Scheme 55

Scheme 56

Drive Motor Generator Battery Cooling Description

The hybrid drive motor battery has two venting systems. One for hybrid battery cooling air and one for venting of possible gases from the hybrid battery vents. The hybrid batteries vent system connects all the battery vents to a rubber manifold that exits the hybrid drive motor battery through a single hose and is vented through the floor panel of the vehicle.

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.

Special Tools

Illustration Tool Number / Description EL 48900 HEV Safety Kit J 46143 Cooling System Adapter J 24460-01 Cooling System Pressure Tester J 38185 Hose Clamp Pliers

Scheme 57

Scheme 58

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Temperature Versus Resistance
• Diagnostic Repair Verification
• Diagnostic Trouble Code (DTC) List - Vehicle
• High Voltage Disabling
• Drive Motor Battery Sensor Module Wiring Harness Replacement
• Air Delivery Description and Operation
• Radiator Surge Tank Replacement (Non-HP2)
• Air Cleaner Assembly Replacement
• Fastener Caution
• Lifting and Jacking the Vehicle
• Approximate Fluid Capacities
• Engine Shield Replacement
• Air Conditioning Condenser Replacement (Gas)
• Transmission Fluid Cooler Pipe Replacement
• High Voltage Enabling
• Drive Motor Generator Control Module Description and Operation
• DTC P0A01-P0A03
• Generator Battery Temperature Sensor Location
• Drive Motor Generator Battery Cooling Description
• Generator Control Module Cooling System Draining and Filling
• Hybrid Cooling System Leak Test
• Hybrid Cooling System Pressure Cap Testing
• Special Tools