GM Service Manual Online
For 1990-2009 cars only

DTC P0A7E ESBBattery Pack Overtemp

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.

Conditions for Running the DTC

    • Engine is running for 30 seconds.
    • The starter/generator control module (SGCM) has received voltage on the ignition 0 voltage circuit.
    • The SGCM has turned ON and no configuration DTC is present.
    • This diagnostic shall run every 100 milliseconds.
    • Reference voltage is stable and accurate.

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 powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The driver information center (DIC), if equipped, may display a message.

Conditions for Clearing the DTC

    • A current DTC Last Test Failed clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Step

Action

Values

Yes

No

Schematic Reference: Starting and Charging Schematics

Connector End View Reference: Engine Electrical Connector End Views

1

Did you perform the Engine Electrical Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Engine Electrical

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 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