GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The BCM, DDM and MSM have an internal voltage sensor that checks the input voltage to determine if it is between 9.0-15.5 V.

The IPC and HCM receive a class 2 message from the BCM notifying these modules of low system voltage.

Conditions for Setting the DTC

The DTC B1983 sets when the battery voltage falls below 9.0 volts.

Action Taken When the DTC Sets

The module stores DTC B1983 as current.

Conditions for Clearing the DTC

In order to clear the DTC from a current status the voltage shall be greater than 9.5 volts for 1.2 seconds.

Diagnostic Aids

Important: If DTC B1982 is set as current in the IPC or HCM use the table to diagnose the failure in the BCM.

Test Description

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

  1. Tests for the proper operation of the complete circuit.

  2. Tests for the proper operation of the battery positive voltage circuit.

Step

Action

Values

Yes

No

Schematic Reference: Control Module References in Body Control System

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, observe the Battery Voltage in the affected module data list.

Does the scan tool indicate the battery voltage is within the specified value?

9.5-15.5 volts

Go to Step 7

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the affected module. Refer to Control Module References in Body Control System.
  3. Measure the voltage from the battery positive voltage circuit of the affected module to the ground circuit of the affected module.

Does the voltage measure near the specified value?

battery voltage

Go to Step 7

Go to Step 4

4

Measure the voltage from the battery positive voltage circuit of the affected module to a good ground.

Does the voltage measure near the specified value?

battery voltage

Go to Step 6

Go to Step 5

5

Test the battery positive voltage circuit of the affected module 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 9

Go to Step 7

6

Test the ground circuit of the affected module 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 9

Go to Step 8

7

Inspect for poor connections at the harness connector of the affected module. 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 9

Go to Step 8

8

Important: Perform the setup procedure for the affected module if applicable.

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

Did you complete the replacement?

--

Go to Step 9

--

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?

--

Go to Step 2

System OK