P0A7E
DTC P0A7E or P1ABE
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P0A7E
- Battery Energy Control Module Hybrid Battery Pack Over Temperature
DTC P1ABE
- Battery Energy Control Module Hybrid Battery Pack Over Temperature
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
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 battery energy control module (BECM) uses the battery temperature sensors to determine the hybrid battery temperature to control the battery cooling fan operation. When the BECM detects a battery temperature rise rate increasing by 2°C (3.6°F) every 20 seconds for 60 seconds this DTC will set.
The HPCM monitors the average battery pack temperature over GMLAN. 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.
Conditions for Running the DTC
* The vehicle power mode is RUN.
* Accessory voltage is 9-18 volts.
Conditions for Setting the DTC
P0A7E
* DTCs P0A9C, P0A9D, P0A9E, P0AC6, P0AC7, P0AC8, P0ACB, P0ACC, P0ACD, P0AE9, P0AEA, and P0AEB are not set.
* The HPCM detects an average battery temperature equal to or more than 73°C (163°F) for 5 seconds.
P1ABE
* DTCs P0A9C, P0A9D, P0A9E, P0AC6, P0AC7, P0AC8, P0ACB, P0ACC, P0ACD, P0AE9, P0AEA, and P0AEB are not set.
* The BECM detects an average battery temperature rise rate of 2°C (3.6°F) every 20 seconds for 60 seconds or the BECM detects 2 battery temperature sensors more than 70°C (158°F) for 5 seconds.
Action Taken When the DTC Sets
P0A7E
* DTC P0A7E is a Type C DTC.
* The HPCM commands the BECM to open the High Voltage contactors Immediately.
P1ABE
* DTC P1ABE is a Type C DTC.
* The HPCM commands the BECM to open the High Voltage contactors when xxx conditions are met.
Conditions for Clearing the DTC
DTCs P0A7E and P1ABE are Type C DTCs.
Diagnostic Aids
Battery temperatures can be affected by vehicle load, outside temperature and customer driving conditions. Test drive the vehicle, try and simulate the conditions this DTC set under.
Check for the following:
* Air inlet and outlet for blockage.
* Loose or poor connections at the BECM temperature sensor harness connector.
* Damage to the BECM temperature sensor harness.
* Damage to the fan or blades.
Special Tools
EL-489000 HEV Safety Kit
Circuit/System Verification
1. Ignition ON, with a scan tool, monitor the hybrid battery temperature parameters. The hybrid battery temperature should be between -39°C (-40°F) and 95°C (203°F).
2. Ignition ON, with a scan tool, command the hybrid cooling fan to 100 percent duty cycle. The inlet air temperature should decrease along with a corresponding decrease in the outlet temperature. Run the fan vent fan for 2 minutes and verify that the battery temp sensors decrease in temperature.
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
Verify that DTCs P0A81, P0A9D, P0A9E, P0A9C, P0AC7, P0AC8, P0AC6, P0ACC, P0ACD, P0ACB, P0AEA, P0AEB, and P0AE9 are not set.
If any of the listed DTCs are set, repair them first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle. Diagnostic Trouble Code Descriptions
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" isolation gloves rated at 1000V with leather protectors
- Visually and functionally inspect the gloves before use.
- Wear the isolation 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.
Ignition ON, with a scan tool, verify the cooling fan is functional in all speed ranges.
1. With a scan tool, monitor all four hybrid battery module temperature sensors for 60 seconds. Verify that hybrid battery temperature parameters are within the conditions for setting.
^ If the conditions for setting the DTC are not met, refer to Diagnostic Aids.
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 upper cover.
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. Check the vent fan for any damage to the fan blades.
^ If fan or blades are damaged replace the battery vent fan.
6. Ignition OFF, disconnect the X3 connector at the BECM.
7. Test the resistance across each temperature sensor 5 volt reference and low reference circuits.
^ If greater than 6 ohms, replace the temperature sensor and sensor harness.
^ If less than 6 ohms, replace the BECM.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair. Verification Tests
* Generator Battery Vent Fan Replacement
* Drive Motor Battery Control Module Harness Replacement