GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 Envoy - 2WD 🢒 Engine 🢒 Engine Electrical 🢒 DTC B1328

Circuit Description

All vehicle modules monitor system voltage. The system voltage message is sent to other modules via Class 2 message. When the system voltage is above the specified range DTC B1328 shall set within the affected module.

Conditions for Running the DTC

This DTC shall run only if the module has power, ground and the ignition is not in START mode. This DTC shall execute regardless of the battery voltage, except when the DTC B1390 is set current.

Conditions for Setting the DTC

This DTC will set as current when the voltage is greater than 15.9 volts for 1.2 seconds and DTC B1390 is not set current in the affected module.

Action Taken When the DTC Sets
    • A message shall be sent out on the class 2 lines to notify all other modules of high than normal 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.

Diagnostic Aids

Using a battery charger to jumpstart the vehicle may set DTC B1328 as a history code.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Tests for the proper voltage at the affected module. If the voltage is not within the proper operating range, the charging system needs to be checked.

    2.

  2. Setup procedure for the module replacement.

Step

Action

Yes

No

1

Did you perform the Engine Electrical Diagnostic System Check?

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, monitor the DTC Information for DTC B1328 in the affected module.

Does the scan tool indicate that DTC B1328 is current?

Go to Step 4

Go to Step 3

3

With a scan tool, monitor the DTC Information for DTC B1328 in the affected module.

Does the scan tool indicate that DTC B1328 is current?

Go to Step 4

Go to Diagnostic Aids

4

Important: Perform the setup procedure for the module setting the code, if necessary.

Replace the module setting the code. Refer to Control Module References in Body Control System.

Did you complete the replacement?

Go to Step 5

--

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?

Go to Step 2

System OK