GM Service Manual Online
For 1990-2009 cars only

Object Number: 491035  Size: SF
Body Control Module Components
Powers, Grounds and Class 2 Data Lines

Circuit Description

The body control module (BCM) receives accessory voltage from the ignition switch through the BCM fuse when the ignition switch is in the accessory or on position. If the BCM senses that the accessory input is inactive, DTC B1382 is set.

Conditions for Running the DTC

    • The engine is running or the ignition 1 input is active for at least 30 seconds.
    • Voltage supplied to the BCM is in the normal operating range (approximately 9-16 volts).

Conditions for Setting the DTC

The BCM does not detect the accessory input after 30 seconds.

Action Taken When the DTC Sets

DTC B1382 is stored in the BCM memory.

Conditions for Clearing the DTC

    • DTC B1382 clears when the code setting condition is no longer present.
    • All BCM history codes will be cleared after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles.

Diagnostic Aids

If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This can often cause the malfunction to appear.

Test Description

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

  1. This step determines if the accessory input is shorted to ground.

  2. This step determines if the BCM is internally shorted.

  3. This step determines if voltage is supplied from the battery to the BCM fuse.

Step

Action

Yes

No

1

Did you perform the Body Control System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Body Control System

2

  1. Install the Scan Tool .
  2. Turn ON the ignition, leaving the engine OFF.
  3. With the Scan Tool , observe the ACCESSORY input parameter in the BCM data list.

Does the scan tool display ON?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Inspect the BCM fuse.

Is the fuse open?

Go to Step 4

Go to Step 6

4

  1. Connect a test lamp between the BCM fuse terminals at the IP fuse block.
  2. Turn ON the ignition, leaving the engine OFF.

Does the test lamp illuminate?

Go to Step 5

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

5

  1. Turn OFF the ignition.
  2. Disconnect the BCM connector C2.
  3. Turn ON the ignition, leaving the engine OFF.

Does the test lamp still illuminate?

Go to Step 8

Go to Step 10

6

  1. Remove the BCM fuse.
  2. Turn ON the ignition, leaving the engine OFF.
  3. Probe both fuse terminals for the accessory circuit at the IP fuse block with a test lamp connected to ground.

Does the test lamp illuminate for one of the terminals?

Go to Step 7

Go to Step 9

7

Test the accessory input circuit for 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 11

8

Repair the short to ground in the accessory input circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the action?

Go to Step 12

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9

Repair the open in the ignition feed circuit to the BCM fuse. Refer to Wiring Repairs in Wiring Systems.

Did you complete the action?

Go to Step 12

--

10

Inspect for poor connections at the harness connector of the BCM. 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 body control module. Refer to Body Control Module (BCM) Programming/RPO Configuration .

Replace the body control module. Refer to Body Control Module Replacement .

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

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