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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2002 🢒 Eldorado 🢒 Engine 🢒 Engine Electrical 🢒 DTC B1983

Circuit Description

The BCM and IPC monitor their input voltages to determine if it is above 9.0 V.

The ACM, IRC, MMM, MSM, and PHN receive a class 2 message from the BCM notifying these modules of high system voltage.

Conditions for Running the DTC

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

Conditions for Setting the DTC

DTC B1982 sets when the battery voltage drops below 9.0 volts.

Action Taken When the DTC Sets
    • A message shall be sent out on the class 2 lines to notify all other modules of high 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 greater than 9.5 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 the ON-Board clearing DTCs feature.
    • Use a scan tool.

Diagnostic Aids

Important: If DTC B1982 is set as current in the ACM, IRC, MMM, MSM, or PHN use the table to diagnose 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.

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

Step

Action

Value(s)

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 and record.

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

9.5 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 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 value recorded in step 2?

--

Go to Charging System Test

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 value recorded in step 2?

--

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