GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The following DTC is for the batteries located in the energy storage box (ESB):

P0A7E is for the hybrid battery pack overtemperature.

Battery temperature sensors allow the energy storage control module (ESCM) to monitor the temperature of the batteries in the energy storage box. The module applies 5 volts to internal input resistors that are connected to the signal circuits of the battery temperature sensors. The module provides ground to the battery temperature sensors through the low reference circuit. The ESCM monitors the voltage drops across the battery temperature sensors and uses the inputs for hybrid calculations. When the battery temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the battery temperatures are hot, the resistances of the sensors are low and the voltage signals are low.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0A7E Hybrid Battery Pack Overtemperature

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The ESCM determines that the value of the battery temperature parameter is greater than 55°C (131°F).

Action Taken When the DTC Sets

    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC

    • The DTC will become history if the ESCM no longer detects a fault.
    • The history DTC will clear after 100 fault-free ignition cycles.
    • The DTC can be cleared with a scan tool.

Step

Action

Value(s)

Yes

No

Schematic Reference: Starting and Charging Schematics

Connector End View Reference: Engine Electrical Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Battery 1,2,3 Temperature parameters in the battery energy control module (BECM) data list.

Does the scan tool indicate that the Battery 1,2,3 Temperature parameters are greater than the specified value?

55°C (131°F)

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3

Does the scan tool indicate that the DTC P0A82 is set current?

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Go to DTC P0A83

Go to Step 4

4

Inspect the energy storage box (ESB) fan ducts for obstructions. Clean or replace as necessary. Refer to Battery Cooling Air Inlet Duct Replacement .

Did you find and correct the condition?

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Go to Step 5

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5

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

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Go to Step 2

System OK