Diagnostic Instructions

DTC Descriptors

DTC P0AAD: Hybrid Battery Pack Air Temperature Sensor 1 Performance

DTC P0AAE: Hybrid Battery Pack Air Temperature Sensor 1 Circuit Low Voltage

DTC P0AAF: Hybrid Battery Pack Air Temperature Sensor 1 Circuit High Voltage

DTC P0AB2: Hybrid Battery Pack Air Temperature Sensor 2 Performance

DTC P0AB3: Hybrid Battery Pack Air Temperature Sensor 2 Circuit Low Voltage

DTC P0AB4: Hybrid Battery Pack Air Temperature Sensor 2 Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
Air Inlet Sensor 5 Volt Reference	P0AAE	P0AAF	--
Air Inlet Sensor Low Reference	P0AAE	P0AAF	P0AAF
Air Outlet Sensor 5 Volt Reference	P0AB3	P0AB4	--
Air Outlet Sensor Low Reference	P0AB3	P0AB4	P0AB4

Typical Scan Tool Data

Hybrid Batt. Inlet Air 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 Battery Inlet Air Temperature Sensor 5 volt Reference Circuit	100°C (212°F)	-40°C (-40°F)	--

Hybrid Batt Inlet Air Temperature 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: 0.5 to 4.3 Volts
Hybrid Batt Inlet Air Temperature Sensor 5 volt Reference Circuit	0 volts	4.75 volts	5 volts

Hybrid Battery Outlet Air 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 Battery Outlet Air Temperature 5 volt Reference Circuit	100°C (212°F)	-40°C (-40°F)	-40°C (-40°F)

Hybrid Batt Outlet Air 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: 0.5 to 4.3 Volts
Hybrid Batt Outlet Air Temp Sensor 5 volt Reference Circuit	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 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 volts 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 BECM uses the air inlet and outlet temperature sensors to determine if air is circulating through the drive motor generator battery assembly.

Conditions for Running the DTC

Conditions for Setting the DTC

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 (18°F) difference for 9 out of 10 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 (18°F) for 9 out of 10 seconds.

Action Taken When the DTC Sets

Conditions for Clearing the DTC

DTCs P0AAD, P0AAE, P0AAF, P0AB2, P0AB3, and P0AB4 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 the hybrid battery air inlet and outlet temperature parameters with a scan tool. The hybrid battery inlet and outlet air temperature should be between -39 and +95°C (-38 and +203°F).
2. Ignition ON, using a scan tool, command the hybrid battery pack fan speed to 60 percent and let run for 2 minutes. The inlet and outlet air temperature parameters should be within 10°C (18°F) of each other.
3. 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 Fame/Failure Records data.

Circuit/System Testing

1. Inspect the inlet air vents for any obstructions or blockages that are external to the drive motor generator battery.

⇒	If no obstructions or blockages are found, continue with diagnosis and proceed to the next step.

⇒	If inlet air obstructions or blockages are found, remove or repair as needed.

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 internal cooling fan inlet duct or outlet duct obstruction.
5. Ignition ON, command the hybrid battery pack vent fan speed through the speed ranges using a scan tool. Verify the hybrid battery vent fan is functional in all speed ranges.
6. Unclip and remove hybrid battery air inlet and outlet temperature sensors and allow them to stand at room air temperature for approximately 3 minutes.
7. Ignition ON, observe the inlet and outlet air temperature parameters with a scan tool. The temperatures should be approximately the same value.

⇒	If the temperature sensor parameters are not approximately the same value, continue to next step.

⇒	If the temperature sensor parameters are approximately the same value, inspect the internal foam seals for damage or if missing and repair as needed. Check for 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 . Both sensors should measure within 500 ohms of each other.

⇒	If greater than the specified value, replace the drive motor battery sensor module wiring harness.

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.