GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The body control module (BCM), driver door module (DDM) and memory seat module (MSM) have an internal voltage sensor that checks the input voltage to determine if it is between 9-15.5 volts.

The instrument panel cluster (IPC) and heating control module (HCM) receive a class 2 message from the BCM notifying these modules of high system voltage.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1982 Right Front/Passenger Seat Front Up Switch Circuit Low

Conditions for Setting the DTC

DTC B1982 sets when the battery voltage raises above 16 volts.

Action Taken When the DTC Sets

Stores a DTC B1982 in the BCM memory.

Conditions for Clearing the DTC

In order to clear the DTC from a current status the voltage shall be less than 15.5 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.

DTC B1982 may set if the vehicle is connected to a battery charger on fast or boost charge.

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 Computer/Integrating Systems

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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 modules data list.

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

9.5-15.5 V

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 Computer/Integrating Systems.
  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

Replace the affected module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

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