Diagnostic Instructions

DTC Descriptors

DTC P0A9C: Hybrid Battery 1 Temperature Sensor Performance

DTC P0A9D: Hybrid Battery 1 Temperature Sensor Circuit Low Voltage

DTC P0A9E: Hybrid Battery 1 Temperature Sensor Circuit High Voltage

DTC P0AC6: Hybrid Battery 2 Temperature Sensor Performance

DTC P0AC7: Hybrid Battery 2 Temperature Sensor Circuit Low Voltage

DTC P0AC8: Hybrid Battery 2 Temperature Sensor Circuit High Voltage

DTC P0ACB: Hybrid Battery 3 Temperature Sensor Performance

DTC P0ACC: Hybrid Battery 3 Temperature Sensor Circuit Low Voltage

DTC P0ACD: Hybrid Battery 3 Temperature Sensor Circuit High Voltage

DTC P0AE9: Hybrid Battery 4 Temperature Sensor Performance

DTC P0AEA: Hybrid Battery 4 Temperature Sensor Circuit Low Voltage

DTC P0AEB: Hybrid Battery 4 Temperature Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
Temperature Sensors 1-4 5 volt Reference	P0A9D, P0AC7, P0ACC, P0AEA	P0A9E, P0AC8, P0ACD, P0AEB	P0A9E, P0AC8, P0ACD, P0AEB
Temperature Sensors 1-4 Low Reference	--	P0A9E, P0AC8, P0ACD, P0AEB	--

Typical Scan Tool Data

Hybrid Batt Mod 1-4 Temperature

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Accessory voltage is 9-18 volts, vehicle power mode is RUN Parameter Normal Range: 26°C (79°F)
Hybrid Batt Mod 1-4 Temperature 5 volt Reference	100°C (212°F)	-40°C (-40°F)	-40°C (-40°F)

Hybrid Batt Mod Temp Sensor

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Accessory voltage is 9-18 volts, vehicle power mode is RUN Parameter Normal Range: 3.2 volts
Hybrid Batt Mod 1-4 Temperature 5 volt Reference	0 volts	4.75 volts	5 volts

Circuit/System Description

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 the Hybrid LAN communication circuit. 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 control module supplies 5 volts 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 determine the hybrid battery temperature to control the battery cooling fan operation.

Conditions for Running the DTC

Conditions for Setting the DTC

P0A9C, P0AC6, P0ACB, and P0AE9

The hybrid battery temperature sensor is in normal operating range, but is at least 15°C (27°F) different from the other 3 sensors.

P0A9D, P0AC7, P0ACC, and P0AEA

The hybrid battery temperature is greater than 95°C (203°F) and at least 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).

Action Taken When the DTC Sets

Conditions for Clearing the DTC

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

Reference Information

Schematic Reference

Hybrid Energy Storage Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit

Circuit/System Verification

1. Ignition ON, observe all four hybrid battery module temperature sensor parameters with a scan tool. The hybrid battery temperature parameters should be between -39 and +95°C (-38 and +203°F) with no more than 15°C (27°F) difference between the four temperature sensors.
2. Operate the vehicle within the Conditions for Running the DTCs. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records Data.

Circuit/System Testing

1. Verify that DTCs P0A80, P0A81 and P0BBD are not set.

⇒	If any of the listed DTCs are set, repair them first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

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.
2. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling .
3. Remove the drive motor generator battery cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement .
4. Verify that there is no cooling fan inlet duct or outlet duct obstruction.

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

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

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

6. 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.
7. Ignition ON, observe all four hybrid battery module temperature sensor parameters with a scan tool, the temperature parameters for all four temperature sensors should all be approximately the same value.

⇒	If all four temperature sensors are not approximately the same value, continue to next step.

⇒

If all four temperature sensors are approximately the same value, the temperature sensors and control module are not at fault. Allow the temperature of the hybrid batteries to stabilize by letting the vehicle stand at room temperature, This could take 4 to 8 hours. Inspect the internal foam seals for damage or if missing and repair as needed. Verify proper cooling fan operation and air flow.

8. Ignition OFF, disconnect the X3 connector at the BECM.
9. Test the resistance across each temperature sensor 5 volt reference and low reference circuits. Refer to Temperature Versus Resistance . All sensors should measure within 500 ohms of each other.

⇒	If greater than 500 ohms, replace the drive motor battery sensor module wiring harness assembly.

⇒	If less than 500 ohms, replace the drive motor generator battery control module and re-install the four temperature sensors. Refer to Generator Battery Temperature Sensor Location for the proper locations.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.