GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 Grand Prix 🢒 Engine 🢒 Engine Electrical 🢒 DTC B1327

Circuit Description

The body control module (BCM) monitors vehicle system voltage. Also, other modules monitor system voltage. The BCM sends a system voltage message to other modules that do not monitor system voltage via Class 2 message.

Conditions for Running the DTC

This DTC shall run only if the BCM has power, ground and the ignition in not in START mode.

Conditions for Setting the DTC
    • This DTC shall be set as current when the voltage falls below 9.0 volts for 1.2 seconds.
    • When the vehicle exits START the module shall delay checking the voltage for 2 seconds.

Action Taken When the DTC Sets
    • A message shall be sent out on the class 2 lines to notify all other modules of low battery voltage.
    • The modules disable the setting of U codes and other DTCs.

Conditions for Clearing the DTC
    • The DTC will clear current status when the voltage is less than 15.5 volts for 1.2 seconds.
    • A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • Use a scan tool.

Step

Action

Value(s)

Yes

No

Schematic Reference: Power Distribution Schematics in Wiring Systems

Connector End View Reference: Power and Grounding Connector End Views in Wiring Systems

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. Operate the vehicle within the conditions for running DTC B1327.

Does the scan tool indicate that DTC B1327 is current in more than 1 module?

--

Go to Step 3

Go to Step 6

3
  1. Turn ON the ignition, with the engine OFF.
  2. With a scan tool, observe the Battery Voltage Signal parameter in the BCM data list.

Does the voltage measure greater than the specified value?

9.4 V

Go to Step 11

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Disconnect the BCM.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage between the battery positive voltage circuit of the BCM and the ground circuit of the BCM.

Does the voltage measure greater than the specified value?

9.4 V

Go to Step 5

Go to Battery Electrical Drain/Parasitic Load Test

5

Measure the voltage between the battery positive voltage circuit of the BCM and a good ground.

Does the voltage measure greater than the specified value?

9.4 V

Go to Step 9

Go to Step 8

6
  1. Turn OFF the ignition.
  2. Disconnect the harness connector of the module setting the DTC B1327.
  3. Measure the voltage between the battery positive voltage circuit of the module setting the DTC B1327 and the ground circuit of the module setting the DTC B1327.

Does the voltage measure greater than the specified value?

9.4 V

Go to Step 10

Go to Step 7

7

Measure the voltage between the battery positive voltage circuit of the BCM or module setting DTC B1327 and a good ground.

Does the voltage measure greater than the specified value?

9.4 V

Go to Step 9

Go to Step 8

8

Test the batter positive voltage circuit of the BCM or module setting DTC B1327 for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

9

Test the ground circuit of the BCM or module setting DTC B1327 for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

10

Inspect for poor connections at the harness connector of the BCM or module setting DTC B1327. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

11

Important: Perform the setup procedure for the BCM or module setting DTC B1327, if necessary.

Replace the BCM or module setting DTC B1327. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

--

Go to Step 12

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12
  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?

--

Go to Step 2

System OK