The drive motor generator battery control module is also referred to as the battery energy control module (BECM). The BECM will diagnose its own systems and determine when a fault condition is present. Diagnostics and system status is communicated from the BECM to the hybrid powertrain control module (HPCM) through serial data. The HPCM is the host controller for diagnostic trouble code (DTC) information.

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 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 BECM uses the battery temperature sensors to control the battery cooling fan operation.

The HPCM monitors the average battery pack temperature over serial data. When the average drive motor generator battery temperature exceeds the calibrated temperature the HPCM will set DTC P0A7E and send a command to the BECM to open the high voltage contactor relays.

P0A7E

The HPCM detects an average battery temperature greater than 73°C (163°F) for 5 seconds.

P1ABE

One of the following conditions exists:

P0A7E

P1ABE

DTCs P0A7E and P1ABE are type C DTCs.

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Battery Venting and Cooling Description

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Special Tools

EL-48900 HEV Safety Kit

1. Verify that DTC P0A81, P0A9C, P0A9D, P0A9E, P0AC6, P0AC7, P0AC8, P0ACB, P0ACC, P0ACD, P0AE9, P0AEA, or P0AEB is not set.

⇒	If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

2. Ignition ON, observe the scan tool BECM hybrid battery temperature parameters. The readings should be between -39 and +65°C (-40 and +149°F).
3. Command the drive motor generator battery vent fan ON in all speed ranges with a scan tool. You should hear the vent fan relay softly click when turned ON and OFF. You should notice a change in fan speed as you increase the commanded speed. There is approximately a 5 second delay from when the battery vent fan speed is commanded before the vent fan speed changes.

Danger: Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:

•	Safety glasses with appropriate side shields when within 50 feet of the vehicle, either indoors or outdoors

•	Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors

-	Visually and functionally inspect the gloves before use.

-	Wear the Insulation gloves at all times when working with the high voltage battery assembly, whether the system is energized or not.

Failure to follow the procedure exactly as written may result in serious injury or death.
1. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling.
2. Remove the drive motor generator battery upper cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement.
3. Verify that there is no cooling fan inlet duct or outlet duct obstruction.

⇒	If obstructed, remove or repair as needed for proper air flow.

4. Inspect the vent fan for any damage to the fan blades.

⇒	If fan or blades are damaged replace the battery vent fan.

5. Unclip and remove all four hybrid battery temperature sensors from the batteries and allow them to stand at room air temperature for approximately 3 minutes. If the batteries are hot, allow them to cool.
6. Ignition OFF, disconnect the X3 harness connector at the BECM.
7. Test for the resistance specified in Temperature Versus Resistance between the signal terminals and the ground terminals of the temperature sensors listed below. All sensors should also be within 500 Ω of each other.

•	Terminals 1 and 2 (battery sensor 1)

•	Terminals 3 and 4 (battery sensor 2)

•	Terminals 5 and 6 (battery sensor 3)

•	Terminals 7 and 8 (battery sensor 4)

•	Terminals 9 and 10 (air inlet sensor)

•	Terminals 11 and 12 (air outlet sensor)

⇒	If not within the specified range, replace the drive motor battery sensor module wiring harness assembly.

8. If all circuits test normal, replace the drive motor generator battery control module.

Temperature Sensor Test

Test for the resistance specified in Temperature Versus Resistance between the signal terminals and the ground terminals of the temperature sensors listed below. All sensors should also be within 500 Ω of each other.

Perform the Diagnostic Repair Verification after completing the repair.