GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The following DTCs are for the battery temperature sensors located in the generator battery carrier on each battery:

    • P0ACB is for the hybrid battery 3 temperature sensor performance.
    • P0AC6 is for the hybrid battery 2 temperature sensor performance.
    • P0A9C is for the hybrid battery 1 temperature sensor performance.

Battery temperature sensors allow the generator battery control module to monitor the temperature of the batteries in the generator battery carrier. 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 generator battery control module 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 Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC P0A9C Hybrid Battery 1 Temperature Sensor Performance
    • DTC P0AC6 Hybrid Battery 2 Temperature Sensor Performance
    • DTC P0ACB Hybrid Battery 3 Temperature Sensor Performance

Conditions for Running the DTC

    • The ignition is ON.
    • The engine has been running for 30 seconds.

Conditions for Setting the DTC

    • P0ACB is set when the generator battery control module has determined that the battery 3 temperature sensor value differs by more than 15 degrees from the average of the 3 sensors.
    • P0AC6 is set when the generator battery control module has determined that the battery 2 temperature sensor value differs by more than 15 degrees from the average of the 3 sensors.
    • P0A9C is set when the generator battery control module has determined that the battery 1 temperature sensor value differs by more than 15 degrees from the average of the 3 sensors.

Conditions for Clearing the DTC

    • The DTC will become history if the generator battery control module no longer detects a fault.
    • The history DTC will clear after 40 fault-free ignition cycles.
    • The DTC can be cleared with a scan tool.

Step

Action

Values

Yes

No

Schematic Reference: Hybrid Energy Storage Schematics

Connector End View Reference: Hybrid Energy Storage 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

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, check for DTCs in the starter generator control module (SGCM).

Are there any DTCs present in the SGCM?

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Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3

Does the scan tool display DTCs P1A22, P1A23, P1A24, P1A26, P1A27, P1A28, P1A29, P1A2A, P1A2B, P1A2D, P1A2E, P1A2F, P1A30, P1A31, P1A32, P1A34, P1A35 or P1A36 set as current or history in the generator battery control module?

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Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 4

4

With the scan tool record the temperature of all 3 temperature sensors and find the average of the 3.

Are all of the battery temperature sensors within 15 degrees of the average?

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Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 5

5

  1. Place the temperature probe of the J 43600 ACR 2000 Air Conditioning Service Center, J39978, Fluke 87, or equivalent on the appropriate out of range battery.
  2. Record the probe temperature.
  3. Compare the probe temperature to the appropriate Battery Temperature parameter on the scan tool.

Is the recorded temperature within the specified value of the scan tool value?

Go to Step 7

Go to Step 6

6

Inspect for poor connections at the harness connector of the appropriate battery temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

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Go to Step 9

Go to Step 8

7

Replace the appropriate battery. Refer to Generator Battery Replacement .

Did you complete the replacement?

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Go to Step 9

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8

Replace the appropriate battery temperature sensor. Refer to Generator Battery Temperature Sensor Replacement .

Did you complete the replacement?

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Go to Step 9

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9

  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 4

System OK