GM Service Manual Online
For 1990-2009 cars only

Circuit Description

DTC B1558 is an internal Body Control Module (BCM) fault.

Conditions for Setting the DTC

The checksum is tested once on wake-up. The fault is set if the running checksum does not match the computed checksum.

Action Taken When the DTC Sets

Stores a DTC B1558 in the BCM memory.

Conditions for Clearing the DTC

    • The conditions for the fault are no longer present.
    • A history DTC will clear after 50 consecutive ignition cycles if the condition for the fault is no longer present.

Diagnostic Aids

    • The DTC may be set as a history DTC with no affect on the control module.
    • If the DTC is retrieved as both a history DTC and a current DTC, the module must be replaced.

Step

Action

Yes

No

Schematic Reference: Body Control System Schematics

1

Perform the Diagnostic System Check for the system exhibiting symptoms.

Did you perform the Diagnostic System Check for the system exhibiting symptoms?

Go to Step 2

Go to Diagnostic System Check for the system exhibiting symptoms

2

Does the scan tool indicate that the DTC is current?

Go to Step 3

Go to Diagnostic Aids

3

Important: Perform the set up procedure for the BCM.

Replace the BCM. Refer to Body Control Module Replacement .

Did you complete the replacement?

System OK

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